GMC Terrain Transmission Problems & Cost | 6T40 / 6T70

The GMC Terrain was equipped with the 6-speed 6T40 transmission and the 6T70 transmission. But they aren’t without their problems though, so let’s look at some of the most common GMC Terrain transmission problems, look at cost estimates and figure out what you can do about them.

Need a replacement transmission? Quality transmission suppliers can be hard to find. Have your 17-digit vehicle VIN# ready. Free estimates sent via text and email.

GMC Terrain Transmission Models

GMC Terrain: 6T70 Transmission
GMC Terrain: 6T40 Transmission

GMC Terrain 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 Terrain Transmission Prices:

TransmissionStreet Smart TransmissionAutozoneAdvance Auto Parts
6T40 / 6T45222025802580
6T75E / 6T70222024002400

What are the DTC codes related to GMC Terrain transmission problems?

P0766 – Failed Shift Solenoid D – This DTC can be stored when there is a problem with a shift solenoid or the valve body.
P2703 – Failed Friction Element D – This trouble code can be triggered by a failed friction element like a clutch disc.
P0720 – Failed Input Speed Sensor or Output Speed Sensor – This trouble code is caused by a bad speed sensor on the transmission.
P0730 – Incorrect Gear Ratio – This issue could be caused by a number of problems, including a fault in the transmission control module, dirty transmission fluid, or a bad transmission solenoid.
P0657 – Voltage Problem in the ‘A’ Circuit – This transmission problem is often caused by a short, or bad ground on the PCM or PCM wiring harness.
P0700 – Malfunction in the transmission control system – This DTC is often triggered when there is a problem with the TCM, a wiring harness, a solenoid, or the valve body.
P0715 – Input/Turbine Speed Sensor Malfunction – This code typically gets stored when the input sensor cannot read the engine RPM, which can prevent the transmission from appropriately shifting gears.
P0717 – Input/Turbine Speed Sensor No Signal – This trouble code is generated when the PCM does not get a signal from the input speed sensor, which will prevent the computer from being able to determine when the transmission needs to shift.
P0791 – Intermediate Shaft Speed Sensor ‘A’ Circuit – This error can occur when there is a problem with the intermediate shaft speed sensor, most likely due to a bad sensor, wiring problem, or a failed shift solenoid.
P0793 – Intermediate Shaft Speed Sensor Circuit No Signal – The computer will generate this DTC when it cannot communicate with the intermediate shaft speed sensor.

GMC Terrain Transmission Recalls

None Found

GMC Terrain Technical Service Bulletins (TSB)

None Found

Common Problems with the GMC Terrain Transmission

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 Terrain 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 Terrain transmission need to be replaced?

The overall lifespan of a GMC Terrain 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 Terrain 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 Terrain transmission issues diagnosed?

It is fairly easy to guesstimate what the root cause of your GMC Terrain 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 Terrain transmission replaced?

In order to replace your GMC Terrain 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 Terrain 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 Terrain transmission here, then find a local shop using our Find a Shop guide to install it for you.

How to Solve GMC Terrain Transmission Problems

Solution A: Buy a Used GMC Terrain 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 Terrain 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 Terrain 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.

Fair Replacement Transmission Cost by Vehicle

  1. Find your transmission model in the table below for fair prices from reputable suppliers. Also fair labor cost for local installation at a local auto repair shop.

  2. Get a free estimate on a remanufactured transmission by email.

Fair Remanufactured Transmission Price Ranges by Transmission Model Updated July 2018

transmission repair cost
Download Replacement Transmission Cost Guide PDF

What Problem Does Your GMC Terrain 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!

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Leave a Comment

PETER SCIFO

2018 GMC TERRAIN SLE. APPROXIMATELY 2000 MILES. VEHICLE BEGAN BEHAVING RADICALLY AT LOW SPEED, JERKING, SLOWING AND HIGH RPMS. IT SEEMED APPARENT IT WOULD NOT SHIFT FROM LOW GEAR. I RAN IT AT ABOUT 25 MILES PER HOUR TO GET IT HOME. A WARNING CAME ON “TRANSMISSION OVER HEATING, IDLE ENGINE”. I PULLED OVER AND IDLED FOR ABOUT 20 MINUTES. THIS HAPPENED 3 TIMES IN ABOUT AN 8 MILE DISTANCE. EACH TIME I WAS ABLE TO CONTINUE AT LOW SPEED UNTIL I GOT IT HOME. CALLED THE DEALER WHO PICKED IT UP. AFTER 4 DAYS THEY SAID THEY COULD NOT GENERATE A CODE OR DUPLICATE THE SYMPTOM. THEY HAVE NO ANSWER AND EXPECT ME TO PICK IT UP. I’VE HAD THE VEHICLE FOR LESS THAN A MONTH (LEASE) AND QUITE FRANKLY DO NOT WANT IT BACK AS I TRANSPORT ELDERLY RELATIVES AND GRANDCHILDREN. THOUGHTS?

Gene Pendak

Hey Peter, I’m currently having the same problem with the exact same mileage. Did you get this rectified and if so, what was the problem? Bringing this in tomorrow to the dealer.

JOAN Gabriello

I was driving my 2018 GMC Terrain at 40 mph when it lost power and slowed down, I stepped on the gas again and same thing happened. I pulled off the road and shut engine off for 15 minutes per instructions from the service dept. the computer reset and the car runs good. Brought it in for a 1-1/2 hour diagnostic visit and they found nothing wrong. I am not happy. I drive on turnpikes with tractor trailers. I am afraid I may get killed if this happens while on the tpk. What can I do?

Amanda

I have a 2018 with 4000 miles on it and it does the same thing for me too.. it’s ok under 30mph but does that herky-jerky thing when I start breaking and slow down at lights or to turn..took it to dealer and of course it doesn’t do it for anyone but me. This thing is a piece of sh*t and a death trap if you ask me. Unfortunately I’m only a few months into my lease. Good luck to you!