If you have experience and skill in automotive repairs, then do it yourself transmission repair may work for you. If, however, you are doing this complex repair yourself simply to save money, be aware first of the disadvantages of repairing your transmission in your backyard or garage.
If your car is still within its manufacturer's warranty period, either by mileage or age, avoid do-it-yourself repair on your transmission. If problems come up that you are unable to fix yourself, and your car needs an authorized transmission repair service, your automobile's entire drive-train warranty will become void.
Damage to Other Drive Train Components
While attempting to fix your transmission, you may damage other parts of the drive train, such as the drive shaft or the universal joint on a front-wheel drive vehicle. You will then have more problems to solve—at greater cost.
Complex Tools Needed to Do the Work
While you can change your transmission fluid, filter and gasket at home, most backyard mechanics do not have the expensive tools, like spring compressors, needed to do complex transmission repairs these days. As well, many transmission problems are now diagnosed electronically by computer. Without the information from these diagnostic tools, you may guess wrong about the problem, and damage the transmission even more.