Designed to be a more stylish and upscale alternative to the 3/4 ton trucks from Chevrolet, Dodge and Ford. The GMC Sierra 2500 HD came equipped with the 4L60E transmission, 4L65E transmission and 4L80E transmission in early models. Later models got the 6L90 6-speed transmission, and the GMC Sierra 2500HD 6.6L Duramax Diesel had the Allison 1000 transmission. But they aren’t without their problems though, so let’s look at some of the most common GMC Sierra 2500 HD transmission problems, look at cost estimates and figure out what you can do about them.
GMC Sierra 2500 HD Transmission Models
GMC Sierra 2500 HD: 4L60E Transmission
GMC Sierra 2500 HD: 4L65E Transmission
GMC Sierra 2500 HD: 4L80E Transmission
GMC Sierra 2500 HD: 6L90 Transmission
GMC Sierra 2500 HD: Allison 1000 Transmission
GMC Sierra 2500 HD Transmission Replacement Cost Estimate
Pricing varies by model. To be 100% sure on pricing, have your VIN# handy and use our Get An Estimate feature to look up your transmission by VIN#.
Replacement GMC Sierra 2500 HD Transmission Prices:
| Transmission | Street Smart Transmission |
|---|---|
| 4L60E / 4L65E | 2100 |
| 4L80E | 2256 |
| 6L80 / 6L90 | 2559 |
| Allison 1000 | 2478 |
What are the DTC codes related to GMC Sierra 2500 HD transmission problems?
| Trouble Code | Description |
|---|---|
| U1000 | Cannot Communicate with TCM / Class 2 Communications Failure |
| U0101 | Lost Communication with TCM |
| U0402 | Invalid Data Received From Transmission Control Module |
| P0218 | Transmission Over Temperature Condition |
| P0700 | Transmission Control System (MIL Request) |
| P0701 | Transmission Control System Range/Performance |
| P0702 | Transmission Control System Electrical |
| P0703 | Torque Converter/Brake Switch B Circuit |
| P0704 | Clutch Switch In put Circuit Malfunction |
| P0705 | Transmission Range Sensor Circuit Malfunction (PRNDL Input) |
| P0706 | Transmission Range Sensor Circuit Range/Performance |
| P0707 | Transmission Range Sensor Circuit Low Input |
| P0708 | Transmission Range Sensor Circuit High Input |
| P0709 | Transmission Range Sensor Circuit intermittent |
| P0710 | Transmission Fluid Temperature Sensor Circuit |
| P0711 | Transmission Fluid Temperature Sensor Circuit Range/Performance |
| P0712 | Transmission Fluid Temperature Sensor Circuit Low Input |
| P0713 | Transmission Fluid Temperature Sensor Circuit High Input |
| P0714 | Transmission Fluid Temperature Sensor Circuit Intermittent P0715 |
| P0715 | Input/Turbine Speed Sensor Circuit |
| P0716 | Input/Turbine Speed Sensor Circuit Range/Performance |
| P0717 | Input/Turbine Speed Sensor Circuit No Signal |
| P0718 | Input/Turbine Speed Sensor Circuit Intermittent |
| P0719 | Torque Converter/Brake Switch B Circuit Low |
| P0720 | Output Speed Sensor Circuit |
| P0721 | Output Speed Sensor Circuit Range/Performance |
| P0722 | Output Speed Sensor Circuit No Signal |
| P0723 | Output Speed Sensor Circuit Intermittent |
| P0724 | Torque Converter/Brake Switch B Circuit High |
| P0725 | Engine Speed Input Circuit |
| P0726 | Engine Speed Input Circuit Range/Performance |
| P0727 | Engine Speed Input Circuit No Signal |
| P0728 | Engine Speed Input Circuit Intermittent |
| P0729 | Gear 6 Incorrect Ratio |
| P0730 | Incorrect Gear Ratio |
| P0731 | Gear 1 Incorrect Ratio |
| P0732 | Gear 2 Incorrect Ratio |
| P0733 | Gear 3 Incorrect Ratio |
| P0734 | Gear 4 Incorrect Ratio |
| P0735 | Gear 5 Incorrect Ratio |
| P0736 | Reverse Incorrect Ratio |
| P0738 | TCM Engine Speed Output Circuit |
| P0739 | TCM Engine Speed Output Circuit Low |
| P0740 | Torque Converter Clutch Circuit Malfunction |
| P0741 | Torque Converter Clutch Circuit |
| P0742 | Torque Converter Clutch Circuit Stuck On |
| P0743 | Torque Converter Clutch Circuit Electrical |
| P0744 | Torque Converter Clutch Circuit Intermittent |
| P0745 | Pressure Control Solenoid 'A' |
| P0746 | Pressure Control Solenoid 'A' Performance or Stuck Off |
| P0747 | Pressure Control Solenoid 'A' Stuck On |
| P0748 | Pressure Control Solenoid 'A' Electrical |
| P0749 | Pressure Control Solenoid 'A' Intermittent |
| P0750 | Shift Solenoid 'A' |
| P0751 | Shift Solenoid 'A' Performance or Stuck Off |
| P0752 | Shift Solenoid 'A' Stuck On |
| P0753 | Shift Solenoid 'A' Electrical |
| P0754 | Shift Solenoid 'A' Intermittent |
| P0755 | Shift Solenoid 'B' |
| P0756 | Shift Solenoid 'B' Performance or Stuck Off |
| P0757 | Shift Solenoid 'B' Stuck On |
| P0758 | Shift Solenoid 'B' Electrical |
| P0759 | Shift Solenoid 'B' Intermittent |
| P0760 | Shift Solenoid 'C' |
| P0761 | Shift Solenoid 'C' Performance or Stuck Off |
| P0762 | Shift Solenoid 'C' Stuck On |
| P0763 | Shift Solenoid 'C' Electrical |
| P0764 | Shift Solenoid 'C' Intermittent |
| P0765 | Shift Solenoid 'D' |
| P0766 | Shift Solenoid 'D' Performance or Stuck Off |
| P0767 | Shift Solenoid 'D' Stuck On |
| P0768 | Shift Solenoid 'D' Electrical |
| P0769 | Shift Solenoid 'D' Intermittent |
| P0770 | Shift Solenoid 'E' |
| P0771 | Shift Solenoid 'E' Performance or Stuck Off |
| P0772 | Shift Solenoid 'E' Stuck On |
| P0773 | Shift Solenoid 'E' Electrical |
| P0774 | Shift Solenoid 'E' Intermittent |
| P0775 | Pressure Control Solenoid 'B' |
| P0776 | Pressure Control Solenoid 'B' Performance or Stuck Off |
| P0777 | Pressure Control Solenoid 'B' Stuck On |
| P0778 | Pressure Control Solenoid 'B' Electrical |
| P0779 | Pressure Control Solenoid 'B' Intermittent |
| P0780 | Shift Malfunction |
| P0781 | 1-2 Shift |
| P0782 | 2-3 Shift |
| P0783 | 3-4 Shift |
| P0784 | 4-5 Shift |
| P0785 | Shift/Timing Solenoid |
| P0786 | Shift/Timing Solenoid Range/Performance |
| P0787 | Shift/Timing Solenoid Low |
| P0788 | Shift/Timing Solenoid High |
| P0789 | Shift/Timing Solenoid Intermittent |
| P0790 | Normal/Performance Switch Circuit |
| P0791 | Intermediate Shaft Speed Sensor Circuit |
| P0792 | Intermediate Shaft Speed Sensor Circuit Range/Performance |
| P0793 | Intermediate Shaft Speed Sensor Circuit No Signal |
| P0794 | Intermediate Shaft Speed Sensor Circuit Intermittent |
| P0795 | Pressure Control Solenoid 'C' |
| P0796 | Pressure Control Solenoid 'C' Performance or Stuck off |
| P0797 | Pressure Control Solenoid 'C' Stuck On |
| P0798 | Pressure Control Solenoid 'C' Electrical |
| P0799 | Pressure Control Solenoid 'C' Intermittent |
| P0810 | Transmission Fluid Pressure Manual Valve Position Switch |
| P0811 | Maximum Adaptive and Long-Term Shift Times |
| P0812 | Transmission Fluid Overtemperature |
| P0813 | Torque Control Solenoid Malfunction |
| P0814 | Torque Converter Overstressed |
| P0816 | Transmission Fluid Pressure Manual Valve Position Switch Park/Neutral with Drive Ratio |
| P0817 | Transmission Fluid Pressure Manual Valve Position Switch Reverse with Drive Ratio |
| P0818 | Transmission Fluid Pressure Manual Valve Position Switch Drive without Drive Ratio |
| P0819 | Internal Mode Switch No Start/Wrong Range |
| P0820 | Internal Mode Switch Circuit A Low |
| P0802 | Transmission Control System Request Circuit/Open |
| P0812 | Reverse Input Circuit |
| P0813 | Reverse Output Circuit |
| P0814 | Transmission Range Display Circuit |
| P0816 | Downshift Switch Circuit |
| P0817 | Starter Disable Circuit |
| P0819 | Up and Down Shift Switch to Transmission Range Correlation |
| P0820 | Gear Lever X-Y Position Sensor Circuit |
| P0821 | Gear Lever X Position Circuit |
| P0822 | Gear Lever Y Position Circuit |
| P0823 | Gear Lever X Position Circuit Intermittent |
| P0824 | Gear Lever Y Position Circuit Intermittent |
| P0825 | Gear Lever Push-Pull Switch (Shift Anticipate) |
| P0826 | Up and Down Shift Switch Circuit |
| P0827 | Up and Down Shift Switch Circuit Low |
| P0829 | 5-6 Shift |
| P0840 | Transmission Fluid Pressure Sensor/Switch A |
| P0841 | Transmission Fluid Pressure Sensor/Switch A Circuit Range/Performance |
| P0842 | Transmission Fluid Pressure Sensor/Switch A Circuit Low |
| P0843 | Transmission Fluid Pressure Sensor/Switch A Circuit High |
| P0844 | Transmission Fluid Pressure Sensor/Switch A Circuit Intermittent |
| P0845 | Transmission Fluid Pressure Sensor/Switch B Circuit |
| P0846 | Transmission Fluid Pressure Sensor/Switch B Circuit Range/Performance |
| P0847 | Transmission Fluid Pressure Sensor/Switch B Circuit Low |
| P0848 | Transmission Fluid Pressure Sensor/Switch B Circuit High |
| P0849 | Transmission Fluid Pressure Sensor/Switch B Circuit Intermittent |
| P0850 | Park/Neutral Switch Input Circuit |
| P0851 | Park/Neutral Switch Input Circuit Low |
| P0852 | Park/Neutral Switch Input Circuit High |
| P0853 | Drive Switch Input Circuit |
| P0854 | Drive Switch Input Circuit Low |
| P0856 | Traction Control Input Signal |
| P0857 | Traction Control Input Signal Range/Performance |
| P0858 | Traction Control Input Signal Low |
| P0859 | Traction Control Input Signal High |
| P0860 | Gear Shift Module Communication Circuit |
| P0861 | Gear Shift Module Communication Circuit Low |
| P0862 | Gear Shift Module Communication Circuit High |
| P0863 | TCM Communication Circuit |
| P0864 | TCM Communication Circuit Range/Performance |
| P0865 | TCM Communication Circuit Low |
| P0866 | TCM Communication Circuit High |
| P0867 | Transmission Fluid Pressure |
| P0868 | Transmission Fluid Pressure Low |
| P0869 | Transmission Fluid Pressure High |
| P0870 | Transmission Fluid Pressure Sensor/Switch C Circuit |
| P0871 | Transmission Fluid Pressure Sensor/Switch C Circuit Range/Performance |
| P0872 | Transmission Fluid Pressure Sensor/Switch C Circuit Low |
| P0873 | Transmission Fluid Pressure Sensor/Switch C Circuit High |
| P0874 | Transmission Fluid Pressure Sensor/Switch C Circuit Intermittent |
| P0875 | Transmission Fluid Pressure Sensor/Switch D Circuit |
| P0876 | Transmission Fluid Pressure Sensor/Switch D Circuit Range/Performance |
| P0877 | Transmission Fluid Pressure Sensor/Switch D Circuit Low |
| P0878 | Transmission Fluid Pressure Sensor/Switch D Circuit High |
| P0879 | Transmission Fluid Pressure Sensor/Switch D Circuit Intermittent |
| P0880 | TCM Power Input Signal |
| P0881 | TCM Power Input Signal Range/Performance |
| P0882 | TCM Power Input Signal Low |
| P0883 | TCM Power Input Signal High |
| P0884 | TCM Power Input Signal Intermittent |
| P0885 | TCM Power Relay Control Circuit/Open |
| P0886 | TCM Power Relay Control Circuit Low |
| P0887 | TCM Power Relay Control Circuit High |
| P0888 | TCM Power Relay Sense Circuit |
| P0889 | TCM Power Relay Sense Circuit Range/Performance |
| P0890 | TCM Power Relay Sense Circuit Low |
| P0891 | TCM Power Relay Sense Circuit High |
| P0892 | TCM Power Relay Sense Circuit Intermittent |
| P0893 | Multiple Gears Engaged |
| P0894 | Transmission Component Slipping |
| P0895 | Shift Time Too Short |
| P0896 | Shift Time Too Long |
| P0897 | Transmission Fluid Deteriorated |
| P0898 | Transmission Control System MIL Request Circuit Low |
| P0899 | Transmission Control System MIL Request Circuit High |
| P0900 | Clutch Actuator Circuit/Open |
| P0901 | Clutch Actuator Circuit Range/Performance |
| P0902 | Clutch Actuator Circuit Low |
| P0903 | Clutch Actuator Circuit High |
| P0904 | Gate Select Position Circuit |
| P0905 | Gate Select Position Circuit Range/Performance |
| P0906 | Gate Select Position Circuit Low |
| P0907 | Gate Select Position Circuit High |
| P0908 | Gate Select Position Circuit Intermittent |
| P0909 | Gate Select Control Error |
| P0910 | Gate Select Actuator Circuit/Open |
| P0911 | Gate Select Actuator Circuit Range/Performance |
| P0912 | Gate Select Actuator Circuit Low |
| P0913 | Gate Select Actuator Circuit High |
| P0914 | Gear Shift Position Circuit |
| P0915 | Gear Shift Position Circuit Range/Performance |
| P0916 | Gear Shift Position Circuit Low |
| P0917 | Gear Shift Position Circuit High |
| P0918 | Gear Shift Position Circuit Intermittent |
| P0919 | Gear Shift Position Control Error |
| P0920 | Gear Shift Forward Actuator |
| P0921 | Gear Shift Forward Actuator Circuit Range/Performance |
| P0922 | Gear Shift Forward Actuator Circuit Low |
| P0923 | Gear Shift Forward Actuator Circuit High |
| P0924 | Gear Shift Reverse Actuator Circuit/Open |
| P0925 | Gear Shift Reverse Actuator Circuit Range/Performance |
| P0926 | Gear Shift Reverse Actuator Circuit Low |
| P0927 | Gear Shift Reverse Actuator Circuit High |
| P0928 | Gear Shift Lock Solenoid Control Circuit/Open |
| P0929 | Gear Shift Lock Solenoid Control Circuit Range/Performance |
| P0930 | Gear Shift Lock Solenoid Control Circuit Low |
| P0931 | Gear Shift Lock Solenoid Control Circuit High |
| P0932 | Hydraulic Pressure Sensor Circuit |
| P0933 | Hydraulic Pressure Sensor Range/Performance |
| P0934 | Hydraulic Pressure Sensor Circuit Low |
| P0935 | Hydraulic Pressure Sensor Circuit High |
| P0936 | Hydraulic Pressure Sensor Circuit Intermittent |
| P0937 | Hydraulic Oil Temperature Sensor Circuit |
| P0938 | Hydraulic Oil Temperature Sensor Range/Performance |
| P0939 | Hydraulic Oil Temperature Sensor Circuit Low |
| P0940 | Hydraulic Oil Temperature Sensor Circuit High |
| P0941 | Hydraulic Oil Temperature Sensor Circuit Intermittent |
| P0942 | Hydraulic Pressure Unit |
| P0943 | Hydraulic Pressure Unit Cycling Period Too Short |
| P0944 | Hydraulic Pressure Unit Loss of Pressure |
| P0945 | Hydraulic Pump Relay Circuit/Open |
| P0946 | Hydraulic Pump Relay Circuit Range/Performance |
| P0947 | Hydraulic Pump Relay Circuit Low |
| P0948 | Hydraulic Pump Relay Circuit High |
| P0949 | Auto Shift Manual Adaptive Learning Not Complete |
| P0950 | Auto Shift Manual Control Circuit |
| P0951 | Auto Shift Manual Control Circuit Range/Performance |
| P0952 | Auto Shift Manual Control Circuit Low |
| P0953 | Auto Shift Manual Control Circuit High |
| P0954 | Auto Shift Manual Control Circuit Intermittent |
| P0955 | Auto Shift Manual Mode Circuit |
| P0956 | Auto Shift Manual Mode Circuit Range/Performance |
| P0957 | Auto Shift Manual Mode Circuit Low |
| P0958 | Auto Shift Manual Mode Circuit High |
| P0959 | Auto Shift Manual Mode Circuit Intermittent |
| P0960 | Pressure Control Solenoid A Control Circuit/Open |
| P0961 | Pressure Control Solenoid A Control Circuit Range/Performance |
| P0962 | Pressure Control Solenoid A Control Circuit Low |
| P0963 | Pressure Control Solenoid A Control Circuit High |
| P0964 | Pressure Control Solenoid B Control Circuit/Open |
| P0965 | Pressure Control Solenoid B Control Circuit Range/Performance |
| P0966 | Pressure Control Solenoid B Control Circuit Low |
| P0967 | Pressure Control Solenoid B Control Circuit High |
| P0968 | Pressure Control Solenoid C Control Circuit/Open |
| P0969 | Pressure Control Solenoid C Control Circuit Range/Performance |
| P0970 | Pressure Control Solenoid C Control Circuit Low |
| P0971 | Pressure Control Solenoid C Control Circuit High |
| P0972 | Shift Solenoid A Control Circuit Range/Performance |
| P0973 | Shift Solenoid A Control Circuit Low |
| P0974 | Shift Solenoid A Control Circuit High |
| P0975 | Shift Solenoid B Control Circuit Range/Performance |
| P0976 | Shift Solenoid B Control Circuit Low |
| P0977 | Shift Solenoid B Control Circuit High |
| P0978 | Shift Solenoid C Control Circuit Range/Performance |
| P0979 | Shift Solenoid C Control Circuit Low |
| P0980 | Shift Solenoid C Control Circuit High |
| P0981 | Shift Solenoid D Control Circuit Range/Performance |
| P0982 | Shift Solenoid D Control Circuit Low |
| P0983 | Shift Solenoid D Control Circuit High |
| P0984 | Shift Solenoid E Control Circuit Range/Performance |
| P0985 | Shift Solenoid E Control Circuit Low |
| P0986 | Shift Solenoid E Control Circuit High |
| P0987 | Transmission Fluid Pressure Sensor/Switch E Circuit |
| P0988 | Transmission Fluid Pressure Sensor/Switch E Circuit Range/Performance |
| P0989 | Transmission Fluid Pressure Sensor/Switch E Circuit Low |
| P0990 | Transmission Fluid Pressure Sensor/Switch E Circuit High |
| P0991 | Transmission Fluid Pressure Sensor/Switch E Circuit Intermittent |
| P0992 | Transmission Fluid Pressure Sensor/Switch F Circuit |
| P0993 | Transmission Fluid Pressure Sensor/Switch F Circuit Range/Performance |
| P0994 | Transmission Fluid Pressure Sensor/Switch F Circuit Low |
| P0995 | Transmission Fluid Pressure Sensor/Switch F Circuit High |
| P0996 | Transmission Fluid Pressure Sensor/Switch F Circuit Intermittent |
| P0997 | Shift Solenoid F Control Circuit Range/Performance |
| P0998 | Shift Solenoid F Control Circuit Low |
| P0999 | Shift Solenoid F Control Circuit High |
| P1702 | Nissan DTC: Transmission Control Module Unable to Access RAM |
| P1703 | Nissan DTC: Transmission Control Module Unable to Access ROM |
| P1705 | Nissan DTC: Throttle Position Sensor Circuit Malfunction |
| P1706 | Nissan DTC: Park Neutral Position Switch Circuit Malfunction |
| P1710 | Nissan DTC: Transmission Fluid Temperature Sensor Circuit |
| P1716 | Nissan DTC: Turbine Revolution Speed Sensor Circuit |
| P1721 | Nissan DTC: Vehicle Speed Sensor MTR |
| P1730 | Nissan DTC: A/T Interlock |
| P1731 | Nissan DTC: A/T 1st Engine Braking / 1-2 Shift Malfunction |
| P1752 | Nissan DTC: Input Clutch Solenoid Valve |
| P1754 | Nissan DTC: Input Clutch Solenoid Valve Function |
| P1757 | Nissan DTC: Front Brake Solenoid Valve |
| P1759 | Nissan DTC: Front Brake Solenoid Valve Function |
| P1762 | Nissan DTC: Direct Clutch Solenoid Valve |
| P1764 | Nissan DTC: Direct Clutch Solenoid Valve Function |
| P1767 | Nissan DTC: High and Low Reverse Clutch Solenoid Valve |
| P1769 | Nissan DTC: High and Low Reverse Clutch Solenoid Valve Function |
| P1772 | Nissan DTC: Low Coast Brake Solenoid Valve |
| P1774 | Nissan DTC: Low Coast Brake Solenoid Valve Function |
| P1821 | Internal Mode Switch Circuit B Low |
| P1822 | Internal Mode Switch Circuit B High |
| P1822 | Internal Mode Switch Circuit B High |
| P1823 | Internal Mode Switch Circuit P Low |
| P1824 | Internal Mode Switch Circuit P High |
| P1825 | Internal Mode Switch Invalid Range |
| P1826 | Internal Mode Switch Circuit C High |
| P1831 | Pressure Control Solenoid Power Circuit Low |
| P1832 | Pressure Control Solenoid Power Circuit High |
| P1833 | GM TCC Solenoid Power Control Circuit Low Voltage |
| P1834 | GM TCC Solenoid Power Control Circuit High Voltage |
| P1835 | Kick-Down Switch Circuit |
| P1836 | Kick-Down Switch Failed Open |
| P1837 | Kick-Down Switch Failed Short |
| P1842 | 1-2 Shift Solenoid Low Voltage |
| P1843 | 1-2 Shift Solenoid High Voltage |
| P1844 | Subaru Transmission Fluid Pressure Sensor A Circuit Intermittent |
| P1845 | 2-3 Shift Solenoid Low Voltage |
| P1847 | 2-3 Shift Solenoid High Voltage |
| P1850 | Brake Band Apply Solenoid Circuit |
| P1851 | Brake Band Apply Solenoid Performance |
| P1852 | Brake Band Apply Solenoid Low Voltage |
| P1853 | Brake Band Apply Solenoid High Voltage |
| P1860 | TCC PWM Solenoid Circuit Electrical |
| P1864 | Torque Converter Enable Solenoid Electrical Fault |
| P1866 | TCC PWM Solenoid Circuit Low Voltage |
| P1870 | Transmission Component Slipping: GM Transmission |
| P1871 | Undefined Gear Ratio |
| P1873 | Torque Converter Clutch Stator Temperature Switch Circuit Low Voltage |
| P1874 | Torque Converter Clutch Stator Temperature Switch Circuit High Voltage |
| P1886 | Transaxle Shift Timing Solenoid Performance |
| P1887 | Torque Converter Clutch Release Switch |
| P1890 | CVT Speed Control System |
| P1891 | Problem in Start Clutch Control System |
| P2700 | Transmission Friction Element A Apply Time Range/Performance |
| P2701 | Transmission Friction Element B Apply Time Range/Performance |
| P2702 | Transmission Friction Element C Apply Time Range/Performance |
| P2703 | Transmission Friction Element D Apply Time Range/Performance |
| P2704 | Transmission Friction Element E Apply Time Range/Performance |
| P2705 | Transmission Friction Element F Apply Time Range/Performance |
| P2706 | Transmission Friction Element F Malfunction |
| P2707 | Shift Solenoid F Performance / Stuck Off |
| P2708 | Shift Solenoid F Stuck On |
| P2709 | Shift Solenoid F Electrical |
| P2710 | Shift Solenoid F Intermittent |
| P2711 | Unexpected Mechanical Gear Disengagement |
| P2712 | Hydraulic Power Unit Leakage Intermittent |
| P2713 | Pressure Control Solenoid D |
| P2714 | Pressure Control Solenoid D Performance or Stuck Off |
| P2715 | Pressure Control Solenoid D Stuck On |
| P2716 | Pressure Control Solenoid D Electrical |
| P2717 | Pressure Control Solenoid D Intermittent |
| P2718 | Pressure Control Solenoid D Circuit Open |
| P2719 | Pressure Control Solenoid D Circuit Range/Performance |
| P2720 | Pressure Control Solenoid D Control Circuit Low Voltage |
| P2721 | Pressure Control Solenoid D Control Circuit High Voltage |
| P2722 | Pressure Control Solenoid E Malfunction |
| P2723 | Pressure Control Solenoid E Stuck Off |
| P2724 | Pressure Control Solenoid E Stuck On |
| P2725 | Pressure Control Solenoid E Electrical |
| P2726 | Pressure Control Solenoid E Intermittent |
| P2727 | Pressure Control Solenoid E Ctrl Circ / Open |
| P2728 | Pressure Control Solenoid E Ctrl Circ Range/Perf |
| P2729 | Pressure Control Solenoid E Ctrl Circ Low Voltage |
| P2730 | Pressure Control Solenoid E Ctrl Circ High Voltage |
| P2731 | Pressure Control Solenoid F |
| P2732 | Pressure Control Solenoid F Performance or Stuck Off |
| P2733 | Pressure Control Solenoid F Stuck On |
| P2734 | Pressure Control Solenoid F Electrical |
| P2735 | Pressure Control Solenoid F Intermittent |
| P2736 | Pressure Control Solenoid F Ctrl Circ/Open |
| P2737 | Pressure Control Solenoid F Ctrl Circuit Range/Performance |
| P2738 | Pressure Control Solenoid F Ctrl Circuit Low Voltage |
| P2739 | Pressure Control Solenoid E Ctrl Circuit High Voltage |
| P2740 | Transmission Fluid Temperature Sensor B Circuit |
| P2741 | Transmission Fluid Temperature Sensor B Circuit Range Performance |
| P2742 | Transmission Fluid Temperature Sensor B Circuit Low |
| P2743 | Transmission Fluid Temperature Sensor B Circuit High |
| P2744 | Transmission Fluid Temperature Sensor B Circuit Intermittent |
| P2745 | Intermediate Shaft Speed Sensor B Circuit |
| P2746 | Intermediate Shaft Speed Sensor B Circuit Range/Performance |
| P2747 | Intermediate Shaft Speed Sensor B Circuit No Signal |
| P2748 | Intermediate Shaft Speed Sensor B Circuit Intermittent |
| P2749 | Intermediate Shaft Speed Sensor C Circuit |
| P2750 | Intermediate Shaft Speed Sensor C Circuit Range/Perf |
| P2751 | Intermediate Shaft Speed Sensor C Circuit No Signal |
| P2752 | Intermediate Shaft Speed Sensor C Circuit Intermittent |
| P2753 | Transmission Cooler Ctrl Circuit Open |
| P2754 | Transmission Cooler Ctrl Circuit Low |
| P2755 | Transmission Cooler Ctrl Circuit High |
| P2756 | Torque Converter Clutch Press Ctrl Solenoid |
| P2757 | Torque Converter Clutch Pressure Control Solenoid Ctrl Circuit Performance or Stuck Off |
| P2758 | Torque Converter Clutch Pressure Control Solenoid Ctrl Circuit Stuck On |
| P2759 | Torque Converter Clutch Pressure Control Solenoid Ctrl Circuit Electrical |
| P2760 | Torque Converter Clutch Pressure Control Solenoid Ctrl Circuit Intermittent |
| P2761 | Torque Converter Clutch Pressure Control Solenoid Ctrl Circuit Open |
| P2762 | Torque Converter Clutch Pressure Control Solenoid Ctrl Circuit Range/Performance |
| P2763 | Torque Converter Clutch Pressure Control Solenoid Ctrl Circuit High |
| P2764 | Torque Converter Clutch Pressure Control Solenoid Ctrl Circuit Low |
| P2765 | Input/Turbine Speed Sensor B Circuit |
| P2766 | Input/Turbine Speed Sensor B Circuit Range/Performance |
| P2767 | Input/Turbine Speed Sensor B Circuit No Signal |
| P2768 | Input/Turbine Speed Sensor B Circuit Intermittent |
| P2769 | Torque Converter Clutch Circuit Low |
| P2770 | Torque Converter Clutch Circuit High |
| P2775 | Upshift Switch Circuit Range/Performance |
| P2776 | Upshift Switch Circuit Low |
| P2777 | Upshift Switch Circuit High |
| P2778 | Upshift Switch Circuit Intermittent |
| P2779 | Downshift Switch Circuit Range/Performance |
| P2780 | Downshift Switch Circuit Low |
| P2781 | Downshift Switch Circuit High |
| P2782 | Downshift Switch Circuit Intermittent |
| P2783 | Torque Converter Temp Too High |
| P2784 | Input/Turbine Speed Sensor A/B Correlation |
| P2786 | Gear Shift Actuator Temp Too High |
| P2787 | Clutch Temp Too High |
| P2788 | Auto Shift Manual Adaptive Learning at Limit |
| P2789 | Clutch Adaptive Learning at Limit |
| P2790 | Gate Select Direction Circuit |
| P2791 | Gate Select Direction Circuit Low |
| P2792 | Gate Select Direction Circuit High |
| P2793 | Gear Shift Direction Circuit |
| P2794 | Gear Shift Direction Circuit Low |
| P2795 | Gear Shift Direction Circuit High |
GMC Sierra 2500 HD Transmission Recalls
None Found
GMC Sierra 2500 HD Technical Service Bulletins (TSB)
TSB 01-07-30-002C – Transmission stuck in third gear with inoperable instrument cluster and multiple DTC’s – 4L60E Transmission & 4L65 Transmission
1999 – 2003 Cadillac Escalade – 2002 – 2003 Cadillac Escalade EXT – 2003 Cadillac Escalade ESV – 1997 – 2003 Chevrolet Silverado – 1997 – 2003 Chevrolet Suburban – 1997 – 2003 Chevrolet Tahoe – 1997 – 2003 Chevrolet Blazer – 1997 – 2003 Chevrolet Express – 1997 – 2003 Chevrolet S10 – 2002 – 2003 Chevrolet Avalanche – 2002 – 2003 Chevrolet Trailblazer – 2002 – 2003 Chevrolet Trailblazer EXT – 1997 – 2003 GMC Sierra – 1997 – 1999 GMC Suburban – 1999 – 2003 GMC Yukon XL – 1997 – 2003 GMC Yukon – 1997 – 2001 GMC Jimmy – 1997 – 2003 GMC Savanna – 1997 – 2003 GMC Sonoma – 2002 – 2003 GMC Envoy – 2002 – 2003 GMC Envoy XL – 1997 – 2003 Oldsmobile Bravada
Problem – Vehicles equipped with the 4L60E and 4L65E transmission may become stuck in third gear, the instrument cluster may not function, and the following DTC’s may be set: P0740, P0753, P0758, P0785 and P1860.
Solution – The most likely cause of this transmission problem is a blown fuse or an open on circuit 1020 between the fuse panel and the transmission. If no battery voltage is found at the fuse, the ignition switch will need to be replaced
TSB 00-07-30-022D – No reverse, second or fourth gears – 4L60E Transmission & 4L65E Transmission
1993 – 2005 GM passenger cars and light duty trucks
Problem – Drivers may experience the loss of reverse, second and fourth gears. First and third gears will seem to function normally
Solution – The reaction sun gear may fail inside of the sun shell. It will need to be replaced with a stronger heat-treated 4L60E / 4L65 sun gear.
TSB 01-04-17-004B – Clunk, bump or squawk when vehicle comes to a stop, or when it is accelerating from a complete stop – 4WD/AWD vehicles with a one-piece propeller/drive shaft only
1999-2004 Cadillac Escalade, Escalade EXT, Escalade ESV – 1996-1999 Chevrolet 1500 Series Extended Cab Short Box Pickup (Old Style) – 1996-1999 Chevrolet 1500 Series Regular Cab Pickup and Utility Models (Old Style) – 1999-2002 Chevrolet Silverado Extended Cab Short Box (New Style) – 1999-2004 Chevrolet Silverado 1500 Series Regular Cab (New Style) – 2000-2004 Chevrolet 1500 Series Avalanche, Suburban and Tahoe – 2001-2004 Chevrolet Silverado 2500/3500 Series Regular Cab with Long Bed or Extended Cab (New Style) – 2001-2004 Chevrolet Silverado 2500 series crew cab, short box (New style) – 1996-1999 GMC 1500 series extended cab short box (Old style) – 1996-1999 GMC 1500 series regular cab pickup and utility models (Old Style) – 1999-2002 GMC Sierra extended cab short box (New style) – 1999-2004 GMC 1500 series Yukon, Yukon XL – 2000-2004 GMC Sierra 2500/3500 series regular cab with long bed or extended cab (New style) – 2001-2004 GMC Sierra 2500 Series Crew Cab, Short Box (New Style) – 2003-2005 HUMMER H2
Problem – In vehicles equipped with 4WD or AWD, drivers may experience a clunk, bump or squawk noise when they come to a stop, or when accelerating from a complete stop. This may occur during the 2-3 upshift or 3-2 downshift.
Solution – Replace the rear driveshaft slip yoke with a more robust nickel plated slip yoke.
TSB 05-07-30-017B – Water contamination – 2004-2006 GMC Sierra 2500 HD 4L60E
Problem – A common transmission problem occurs when the transmission shudders/shakes between 40 and 50 mph, as the torque convertor clutch engages. This is caused by rain water getting into the transmission through the dipstick.
Solution – The air inlet grille panel will have to be modified according to the procedure outlined in the TSB.
TSB PIP4051C – Harsh Shifting – GMC Sierra 2500 HD 4L60E
Problem – Unusually harsh gear changes, combined with a P0717 DTC for an input shaft speed sensor error, are often caused by damage to the ISS sensor wiring.
Solution – If wire damage is found (usually to the white wire), the wiring and sensor will have to be replaced. The pump cover should also be examined for sharp points/edges that could damage the wiring. If any are found, they should be smoothed with a file.
TSB 04-07-30-028A – Transmission fluid leak from reverse servo cover – 4L65E
Problem – An ATF leak can occur under the vehicle during cold weather (temperature below 20°F/6.7°C), due to a failed reverse servo cover seal.
Solution – To remedy the problem, an upgraded (see: better quality) reverse servo cover seal will have to be installed.
TSB 08-07-30-016 – Slipping, refusal to shift, overheating GMC Sierra 2500 HD 4L80E
Problem – Slipping between the gears, overheating, refusal to shift out of a gear, and/or DTC P0894 or P0218, may be because by friction material debonding from the torque convertor clutch (TCC).
Solution – If the friction material has circulated throughout the transmission, the entire transmission may need to be replaced. It is possible to remove the material from the internal components (like transmission cooler lines and the valve body), but it depends on the extent of the damage.
TSB 08-07-30-001 – 2001-2006 GMC Sierra 2500 HD 4L80E
Problem – Harsh or delayed shifts, slipping, no forward/reverse gears. Possible DTCs: P0741, P0742, P0751, P0752, P0756, P0757, P0894.
Solution – Rebuild or replace the valve body.
TSB 08-07-30-015 – 2002-2007 GMC Sierra 2500 HD 4L80E
Problem – Harsh shifts, delayed 2-3 shifts, 2-3 shift flare, no 3rd gear, slips in 3rd gear or reverse. Possible DTC 0757.
Solution – If none of the issues described in Bulletin 08-07-30-001 are present (debris in #11 checkball, leak in oil circuit, damage to the direct clutch), then replace the 2-3 shift solenoid due to a possible sticking pintle.
TSB PI488C – No forward or reverse and/or slipping – 6L80 Transmission | 6L90 Transmission
2010 – 2014 Cadillac CTS-V – 2010 – 2014 Cadillac Escalade (all models) – 2010 – 2013 Chevrolet Avalanche – 2010 – 2014 Chevrolet Camaro – 2010 – 2014 Chevrolet Corvette – 2010 – 2014 Chevrolet Express – 2010 – 2014 Chevrolet Silverado – 2010 – 2014 Chevrolet Suburban – 2010 – 2014 Chevrolet Tahoe – 2011 – 2014 Chevrolet Caprice PPV – 2014 Chevrolet SS – 2010 – 2014 GMC Savanna – 2010 – 2014 GMC Sierra – 2010 – 2014 GMC Yukon – 2010 – 2014 GMC Yukon XL – 2010 – 2014 GMC Yukon Denali
Problem – Trucks equipped with the 6-speed 6L80 or 6L90 transmission may experience no forward or reverse engagement, or slipping between the gears.
Solution – This problem could be caused by a cracked or split transmission filter. If this is the case, the transmission pump should be disassembled and inspected for possible damage. Inspect for any of the following conditions: – scored pump rotor or pump vanes – scored pump cover or pump rotor pocket – cracked pump slide.
The transmission should also be evaluated for any possible distress to the clutches. GM’s testing and analysis found that split or damaged filters may be caused by a damaged transmission pump. This can send a high pressure fluid spike down the filter neck on a cold start, resulting in the filter body cracking or the filter seam splitting. The filter is not defective and this is not a filter quality issue. Important: Do not replace the filter without inspecting the pump. Failure to inspect the pump and clutches could lead to a repeat of this condition.
TSB 09-07-30-004J – Slips in Reverse or Third, Delayed Reverse or Drive Engagement, DTC P0776, P2715, P2723, Harsh 2-3 Shifts – 6L80 Transmission | 6L90 Transmission
2006-2009 Cadillac STS-V – 2006-2009 Cadillac XLR – 2006-2009 Cadillac XLR-V – 2007-2008 Cadillac Escalade, Escalade ESV, Escalade EXT – 2006-2009 Chevrolet Corvette – 2007-2008 Chevrolet Silverado – 2008 Chevrolet Suburban – 2007-2008 GMC Sierra – 2007-2008 GMC Sierra Denali – 2007-2008 GMC Yukon Denali – 2007-2008 GMC Yukon XL Denali – 2008 GMC Yukon XL – 2008-2009 HUMMER H2 – 2008-2009 Pontiac G8
Problem – Vehicles equipped with the 6L80 or 6L90 transmission may slip when Reverse is selected or have no/delayed reverse engagement, harsh shifts from 2-3 / 4-5 or slips while in fifth, and slipping acceleration when passing. Possible DTCs include P0776, P2715 or P2723.
Solution – This transmission problem may be caused by a cracked 1-2-3-4 / 3-5-R clutch housing.
TSB 14043 – Thrust bearing failure – Allison 1000 Transmission
2012 Chevy Silverado HD – 2012 GMC Sierra HD
Problem:
Certain 2012 Chevrolet Silverado 2500HD / 2012 Chevrolet Silverado 3500HD and 2012 GMC Sierra 2500HD / 2012 GMC Sierra 3500HD trucks equipped with the Allison 1000 6-speed automatic transmission (MW7), may have been built with an incorrect transmission thrust bearing. Over time, this bearing could fail, resulting in noise and poor transmission operation.
Solution:
The bearing should be replaced with GM part # 29531106
TSB PIP3598C – Intermittent ratio codes or range inhibit – Allison 1000 Transmission
2007 – 2012 Chevrolet Silverado – 2001 – 2007 Chevrolet Silverado Classic – 2007 – 2012 GMC Sierra – 2001 – 2007 GMC Sierra Classic – 4WD Only
Problem – Drivers may experience intermittent no forward or reverse condition, the possibility of a flashing PRNDL display or a “range shift inhibited” message in the driver information center with no saved DTCs. Another possible symptom includes the following DTCs: P0729, P0731, P0732, P0733, P0734, P0735 & P0736
Solution – These Allison 1000 transmission problems may be caused by either an input speed sensor and or output speed sensor issue. The problem could also be caused by a mechanical issue inside of the four-wheel-drive transfer case like a worn bushing.
TSB 14308 – Leak at transmission cooler
2008 Chevy Silverado HD – 2008 GMC Sierra HD
Problem – Diesel powered 2008 Chevrolet Silverado 2500HD / 2008 Chevrolet Silverado 3500HD and 2008 GMC Sierra 2500HD / 2008 GMC Sierra 3500HD trucks equipped with the Allison 1000 6-speed automatic transmission (RPO MW7), may have a condition in which increased transmission oil cooling circuit pressure may cause transmission fluid to weep or leak. This loss of fluid occurs near the transmission cooler at the crimp joints on the metal ends of the cooler line where it joins the rubber hose. The increased oil cooling circuit pressure typically occurs while driving in extremely low temperatures.
Solution – Inspect and replace cooler lines if necessary.
TSB 04-07-30-018A – Ice buildup on shift cable – Allison 1000 Transmission
2001-2006 Chevrolet Silverado 2500HD – 2001-2006 GMC Sierra 2500HD
Problem – In cold climates, it may not be possible to shift the transmission after operating it in snow, slush, or icy conditions. This is likely due to ice buildup around the shift cable-to-manual shaft connection.
Solution – Install an aftermarket transmission shield.
TSB 06-07-30-013 – Shudder in 6th gear – Allison 1000 Transmission
2006 Chevrolet Silverado 2500HD – 2006 GMC Sierra 2500HD
Problem – Owners may experience a shudder occurs in 6th gear in 4Hi between 46 mph (74 km/h) and 49 mph (79 km/h).
Solution – Reprogram the TCM with TIS version 6.0 or higher.
TSB 08-07-30-049A – Transmission fluid leak from the ATF cooler – Allison 1000
2006-2007 Chevrolet Silverado Classic 2500 – 2007-2009 Chevrolet Silverado 2500HD – 2007-2009 GMC Sierra 2500HD
Problem – ATF leak coming from one of the transmission cooler lines.
Solution – Replace lines with updated design: GM Part #’s 20759971 (upper), 20759972 (lower), 20759971 (hose).
TSB 10-07-30-008A – Transmission won’t shift into overdrive – Allison 1000
2006-2010 Chevy Silverado HD – 2006-2010 GMC Sierra HD
Problem – Owners may experience a failure to shift into overdrive, or a 4-5 shift flare. Possible DTC P0777 or P0735.
Solution – Inspect and possibly replace the 3rd, 5th, and reverse clutch piston.
PIP4290A – Engine Stalling – Allison 1000
2007-2013 Chevrolet Silverado HD – 2007-2013 GMC Sierra HD
Problem – Owners may experience stalling or surging when stopped with the transmission in gear. Possible DTC P0742.
Solution – Inspect and replace the TCC solenoid and valve inside the valve body.
Common Problems with the GMC Sierra 2500 HD Transmission
Intermittent harsh shifting – GMC Sierra 2500 HD 4L60E
Problem – A common Chevy Silverado transmission problem is an intermittent hard 1-2 shift, often accompanied by engine bogging. This condition can be caused by the torque convertor clutch applying during the shift.
Solution – To remedy the problem, the wiring harness needs to be inspected from the transmission case connector to the rear of the engine on the driver side. It’s possible that the wires for the TCC solenoid and pressure control solenoid have become frayed on a body seam. If this is the case, the wiring will need to be repaired, and the harness repositioned.
Solenoid DTC’s – GMC Sierra 2500 HD 6L90E
Problem – A number of diagnostic trouble codes, including P0776, P0796, P2714 and P2723, can be caused by a pressure leak at the end of the clutch regulating valve.
Solution – The bore plug will have to be replaced with updated versions, or modified to accept an O-ring kit.
Lack of Response
Leaking Fluid
Low Fluid
Burning Smell
Grinding or Shaking
Whining, Clunking or Humming
Refuses to Go Into Gear
Torque Converter Issues
Valve Body Issues
Transmission Noisy in Neutral
Gears Slipping
No 3rd or 4th Gear
No 1st or 2nd Gear
No Reverse
Dragging Clutch
Trouble Codes / Check Engine Light
Can I drive with a transmission problem?
If your GMC Sierra 2500 HD can still make it up and down the road, you might say “It’s fine, I’ll just drive it until I can get it fixed”. But that is not always a good idea, depending on the symptoms. You see, there are a lot of (very expensive) moving parts inside of a transmission, and if something isn’t right, continuing to drive with a transmission problem could damage something else.
How often does a GMC Sierra 2500 HD transmission need to be replaced?
The overall lifespan of a GMC Sierra 2500 HD transmission largely depends on how well it was maintained. Factory design flaws also factor into this equation, along with how/how hard you drive. But on average, we’ve seen the GMC Sierra 2500 HD transmission last for between 130,000-180,000 miles. A high quality replacement transmission however, can last considerably longer if all of the factory design flaws have been addressed and the vehicle has been maintained.
How are GMC Sierra 2500 HD transmission issues diagnosed?
It is fairly easy to guesstimate what the root cause of your GMC Sierra 2500 HD transmission problems might be, but you won’t truly know unless you have the right tools and experience. A good mechanic or transmission repair center will be able to connect your truck to a computer and find out which diagnostic trouble codes (DTC’s) have been stored. Once they know what to look for, they can perform a visual inspection to verify the problem.
How is a GMC Sierra 2500 HD transmission replaced?
In order to replace your GMC Sierra 2500 HD transmission, the truck has to be lifted from the ground in order to gain access to all of the parts that will need to be unbolted. Then the transmission can be lowered to the ground (typically with a transmission jack), so the new transmission can be installed. Once it is in place, for the 6L80, the vehicle PCM will have to be reprogrammed / reflashed to accept the new transmission using the latest GM subscription.
Recommendations for GMC Sierra 2500 HD transmission issues?
To save time and get back on the road faster, have your 17-digit truck VIN# handy and you can get an online quote for a reman GMC Sierra 2500 HD transmission here, then find a local shop using our Find a Shop guide to install it for you.
How to Solve GMC Sierra 2500 HD Transmission Problems
Solution A: Buy a Used GMC Sierra 2500 HD Transmission
The quickest way to fix your transmission problems is to simply buy a used transmission or used transmission. These can be found at most junk yards, and they often come with a 30-90 day warranty. However, there’s no way to determine the actual condition of the internal components, so you could be spending a bunch of money to have the exact same problems. Plus, that warranty only covers the transmission if it’s defective, not the labor costs that you’ll have to pay.
Solution B: Buy a Rebuilt GMC Sierra 2500 HD Transmission
Another option would be a rebuilt transmission or rebuilt transmission. A local repair shop will remove your transmission, then install a bunch of new parts during the rebuild. The problem here is, the skills and experience of each transmission rebuilder will vary widely from shop to shop, so you could have problems from something that wasn’t adjusted properly. And the 1-2 year warranty might only cover you at certain transmission repair shops, in a specific geographical area.
Solution C: Buy a Remanufactured GMC Sierra 2500 HD Transmission
Many owners depend on their vehicle to commute and get things done. Their gasoline engines are designed to go 100’s of thousands of miles, so it makes sense to invest in a remanufactured transmission.
What Problem Does Your GMC Sierra 2500 HD Have?
Let us know the year, mileage and problem you’re having as well as any trouble (OBD) codes you’ve found. If you’ve been given a quote or paid for a repair, we’d like to hear about that too!

Rabge shift inhibited
Transmission engages hard from park or neutral into drive
2006 GMC Sierra 2500 6.6 four-wheel drive as I’m going down the road it’s like the transmission just starts slipping and it makes the engine rev real high and then I let off of it and it starts going again
2002 GMC Sierra 2500HD AT gas engine,207K miles is making metalic pulsating whirring noise that does not go away when in gear, intermittently slips out of gear at 0-30mph, revs then clunks and lurches forward into gear, transmission fluid mid range on dip stick but fluid spray in engine compartment, could not find source of leak, topped up. Error codes P0700, P0732, P0841, P0848, P0871, P0875
Transmission problem started on my 2013 2500 Sierra when I had a radiator replaced – took 4 new radiators until finally had to order from GMC . First three were from Napa which leaked at the inlet lines for transmission and oil cooler. After the GM radiator was installed we started noticing a rumbling noise at 40-50 mph. Took it back to repaire shop and had it looked at . Service tech said it was in Drive train and referenced me to his transmission man – which quoted me at $3,700. For complete rebuild before he even looked at it ? Don’t know but this sounds like a hustle . Funny how my truck was fine and only needed a radiator and the transmission noise started immediately after the third radiator was installed? My thought if it’s not a scam that the transmission either overheated from the faulty radiators or the fluid was contaminated. Any help would be greatly appreciated
Thanks
When I go to back up it clunks and it feels like you ran into something
Just replaced all the brakes on my GMC 2500 HD 6.0 drove 20 miles first started hearing a whining went another mile and it won’t shift no forward gears only reverse
Sitting at stoplight transmission will come out of gear engine will rev and and then clunk back into gear
2018 GMC Denali Duramax. Drove it out and everything seemed fine on our long private road as i was only going 18 20 mph then as a drive out onto the main road and tried to accelerate it hit 30 33 mph and wouldn’t go any faster the rpm’s we’re at 3,000 and there was white smoke coming from the exhaust, i pulled over to turn around and go back home and i tried to reverse and it wouldn’t move so it only goes forward and only 20 25 mph
I have a 2006 GMC Diesel, Allison Transmission, Sierra 2500 with 230,000 miles in it. I have slippage in 6th gear showing up on my Banks power display. There are no codes and the slippage with and without load on highway usage is between 12 and 17. Any thoughts?
Transmission will not go into gear. Shifter will move, will not go into gear. When it first stalled it would move, however top speed was 25mph and now won’t go into gear
It always seem to run hot
If I’m in the pedal any it won’t shift, when i let off the gas it shifts. Mainly 3rd and 4th gear.
2006 GMC 2500 4l80 I think
95 GMC 2500 4×4 bought the truck used was told transmission was bad bought used 4l60E with converter went and purchased all new seals fluids got it put together the thing had sat for a couple years wasn’t sure it would even run but fired right up no issues made sure fluids were topped took it around the block less then half way it started leaking fluid on to exhaust from front seal, was told the seal was damaged so pulled out replaced the seal again same thing so I pulled Transmission again last night hung it from engine hoist strapped down to cart put another seal in put the converter back on let it sit for a few hours no sign of leak went back and fluid has pooled up right at the bottom of seal the everything looks good fluid looks normal seals not torn no damage to the spline IM AT A LOSS AS WHAT IS NEXT