A rebuilt transmission is a collection of parts that must work together in perfect harmony. There can be over 1,000 individual parts that range from tiny springs to big heavy gears. When a transmission rebuild is performed, new ‘soft parts’ like seals and clutch discs are mixed with existing ‘hard parts’ like gears and pumps. On average, a rebuilt transmission is expected to last between 30,000 – 50,000 miles. If the work is done extremely well and regular maintenance is performed, a transmission rebuild can last as long as the original transmission (120,000 – 200,000 miles on average). There are however, a number of things that factor into rebuilt transmission reliability like the quality of the rebuild, the condition of the transmission that was rebuilt and maintenance/driving style.
What Transmission Do I Have?
Things that affect how long a transmission rebuild will last
Rebuild quality – If the person rebuilding the transmission isn’t careful and thorough, they could miss small defects in the metal hard parts that could significantly reduce the lifecycle of the rebuilt transmission. Most mechanics and transmission repair shops are quite competent at what they do. However, many shops don’t have the equipment and experience to know where to look for problems. Let alone the knowledge of how to prevent problems common to different transmission types. This can obviously reduce the amount of time that a rebuilt transmission will last, and require additional warranty work and/or out-of-pocket repairs. \\
Transmission condition – Since a rebuilt transmission is based on the transmission that you already have. The condition of the internal components will play a major role in how long the transmission rebuild lasts. Things like broken gears and other components can cause small metal fragments to be circulated throughout the gearbox and valve body. This can cause abrasions, scoring and cracks that may not be immediately apparent to the naked eye. Over time, those little defects can become much bigger defects, cause hydraulic pressure loss inside the transmission, as well as a number of other problems that can significantly reduce the lifespan of your rebuilt transmission.
Transmission maintenance – Changing the transmission filter and fluid every 30,000 – 50,000 miles is absolutely essential if you want to make your rebuilt transmission last. Transmission fluid is designed to remove heat caused by the friction from all those moving parts. If the ATF starts to break down, the transmission will start to run hot and/or overheat. Causing significant damage to the metal parts, seals, friction elements and other components inside the transmission. So if you expect your transmission rebuild to last, check and change your transmission fluid regularly.
Driving style – Heat is the Achilles’ heel of an automatic transmission. Excessive heat is caused not only by poor maintenance, but also by driving/use style. If you drive, shall we say ‘vigorously’, then your transmission temperature will regularly run on the high side as you race away from the stoplight or force a downshift to pass people. This scenario also applies to driving in the mountains or hilly terrain. Regularly towing heavy loads or hauling heavy loads inside the vehicle (which can apply to many commercial applications), can also put a lot of strain on your rebuilt transmission. If any of these scenarios applies to you, you should do your self and your transmission a favor and get an auxiliary transmission cooler installed. This will allow the transmission fluid to expel significantly more heat before it returns to the transmission, resulting in lower temperatures and less wear on the internal components.
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.
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.
What Transmission Do I Have?
