An automatic transmission is one of the most complex mechanical devices in a vehicle. Although an engine is definitely complicated, it takes a lot of mechanical wizardry to turn an engine’s power into motion. Automatic transmissions weren’t even introduced for almost a full half-century after the car was invented. The idea was to take the rotational power created by the engine crankshaft and turn it into hydraulic pressure that could change gears inside the transmission when a specific engine RPM was reached. A lot of complicated components are required to make this happen, which is why performing a transmission rebuild is not a simple task.
What Transmission Do I Have?
Step One: Remove the transmission
The transmission in most RWD vehicles is fairly simple to remove. Simply remove the driveshaft, remove the transmission mount/support then unbolt the bell housing from the engine. FWD vehicles are usually not that simple. The automatic transmission is typically located underneath the engine on the driver’s side of the engine compartment. This usually means that the engine has to be partially removed from the vehicle, or part of the subframe underneath the vehicle has to be removed. Either way, this is usually a difficult and time-consuming task.
Step Two: Disassemble the transmission
The internal components inside the transmission have to be removed in sequence, using special tools to remove different clips and other attaching hardware that holds various components in place. All of the transmission parts also have to be cleaned and carefully inspected for signs of damage and wear.
Step Three: Reassemble the transmission
At this stage of the transmission rebuild, all of the new components like seals, gaskets, clutches, bearings and bushings have to be installed. Special care has to be taken in order to ensure that everything is installed correctly. Otherwise there will be serious leaks and hydraulic pressure loss. Rebuilding the valve body is also very time-consuming due to the complexity of it. There are lots of small springs, check balls and valves that have to be removed and replaced. The valve body is essentially the brains of the transmission, as it’s responsible for directing the flow of the pressurized hydraulic fluid to activate the different gears. Extra care has to be taken to ensure that there are no cracks, warps or scoring inside of the holes where the valves live. Needless to say, this entire process can take many hours.
Step Four: Reinstall the rebuilt transmission and road test
Obviously, reinstalling a fresh transmission rebuild is the reverse of the removal process. But once it’s done, the vehicle has to be road tested to be sure that the newly rebuilt transmission performs the way it’s supposed to. If it doesn’t, it may have to be disassembled once more so that adjustments can be made.
So is rebuilding a transmission difficult?
The answer to this question largely depends on the skill of the rebuilder. If a mechanic has a lot of experience rebuilding a particular type of transmission, the process can go quickly and smoothly. Technicians with less experience may have a more difficult time and not know all of the different places to look for damage, as well as the different updates and upgrades they need to do in order to extend the lifecycle of the transmission.
Things to consider with a transmission rebuild
You’re the test driver – Most transmission repair shops and mechanics will only put a few miles on your vehicle to make sure the transmission works. But it’s not uncommon to experience transmission problems during the break-in period.
Everything might not be fixed – Most mechanics and transmission repair centers don’t have the equipment necessary to perform a thorough inspection on hard parts like gear sets, clutch drums and valve bodies. This means that your rebuilt transmission could actually have small cracks in key parts that aren’t visible to the naked eye. As time and mileage progress, these cracks can grow and create an even larger problem. Similarly, a slight warp in the valve body can seriously impact shifting performance over time.
Warranty – Although most mechanic shops and transmission repair shops will warranty their work. That coverage is usually only good at the shop or franchise that did the work. If you travel out of town and suddenly experience transmission problems, you’ll be on the hook for any transmission repairs unless you pay to have your vehicle towed back to the shop that did the work.
Quality – Nearly every time you get a transmission rebuild, all of the work is performed by a single technician. This may or may not be a good thing, depending on your point of view. But the end result is dependent on that technician’s level of experience working with your specific type of transmission. In addition, there is usually no standardized quality control checks at a mechanic shop. So an improperly torqued bolt or gasket that isn’t fully seated, might be overlooked and cause you major problems in the future.
Why a remanufactured transmission might be a good option
While you can’t buy a brand-new transmission, a remanufactured transmission is a terrific alternative. These are completely reengineered and put together on a factory assembly line. They often contain a lots of upgrades over their stock form, which means many of the design flaws that result in premature failure of components can be eliminated. This can give a reman transmission a much longer service life than it originally had.
Remanufactured transmission companies like Street Smart Transmission put each of their reman transmissions through a rigorous build process that ensures a quality product every time. It starts with nearly 100 trained technicians that specialize in different aspects of the build process.
This remanufacturing process starts with the inspection team that test all of the critical components from the donor transmission to ensure that they meet the original equipment (OE) tolerances and specifications. The case, pumps, gears, shafts, valve body and torque converter are checked for hairline cracks, metal tensile strength, warping and other parameters. If any component fails to meet the required specifications, it’s discarded and replaced.
All the parts are then cleaned and sent to the appropriate stations on the assembly line for reassembly. Throughout the process, quality control managers inspect the build to ensure that it meets the desired specification. Any necessary modifications or upgrades that are needed to correct factory design flaws are also performed or added. The valve body is rebuilt and tested on a special dyno machine to ensure that it performs according to the specifications. All of the solenoids are also tested prior to installation.
Once the build is complete and passes its final quality control inspection, the newly remanufactured transmission is sent to the dyno room, where it’s tested on a special dyno machine using a proprietary software program called C.A.R.S. (Computer Aided Real-world Simulation). This cycles the transmission through a number of real-world driving situations, to ensure that it performs according to the factory specs. It also helps to break in all of the friction components, that way it’s completely tuned and ready to go once it’s installed.
What Transmission Do I Have?
Warranty – One of the benefits of buying a remanufactured transmission vs. a rebuilt transmission is the warranty. Street Smart Transmission for example, covers all of their reman transmissions with a 3 Year/Unlimited Mileage Nationwide Warranty (there is a mileage restriction for commercial vehicles). This covers parts and labor for transmission repairs performed by any licensed repair shop in the country. It’s also completely transferable if you ever decide to sell the vehicle. Compared to a mechanics warranty on a transmission rebuild, a remanufactured transmission warranty offers superior financial protection.
