There isn't much that a shade tree mechanic can do to repair an automatic transmission but there are some simple things you can do to extend the time before problems arise.
The automatic transmission is one of the most expensive components on your car to have serviced. I said have serviced because there are remarkably little that a shade tree mechanic can do in the way of servicing an automatic transmission. The shade tree mechanic may have the knowledge, but remarkably, few have the specialized tools or facilities to overhaul an automatic transmission. The tools are expensive, and the work itself must be performed under "Clean Room" conditions. There is not much that you can do to repair an automatic transmission, but there are things that you can do to keep them trouble free. In this article, I am going to talk about a few things that you should not do.
1. Do Not Park Your Car Without Engaging The Parking Brake.
Do not do as many drivers do, do not park your car with the transmission gear selector in "Park" without applying the "Parking Brake." The "Parking Pawl," the tiny metal part that locks the output shaft of your transmission when it is placed in "Park" was not meant to be used as a "Parking Brake." Even the lightest of taps by another car can break the pawl. A broken parking pawl will allow your car to roll into traffic. Pieces of the broken parking pawl can cause serious damage to other transmission parts.
2. Do Not Use An Automatic Transmission As A Brake.
Many of us learned to drive in the days when standard shifts were the rule rather than the exception. We were taught to downshift as we approached a light. We were taught to downshift when descending a steep slope. We were taught to use the engine as a brake. Many drivers have carried that practice over to cars with automatic transmission. Not an acceptable practice. A forced downshift at high-engine RPMs causes excessive wear to the transmission's clutch friction plates and the transmission's friction bands.
3. Do Not Shift Into Gear While The Engine Is On Fast Idle
Do not shift from "Neutral" or "Park" into any gear while the engine is at fast idle. This sudden, jarring engagement places increased stress on the clutch plates and bands. It placed increased stress on the planetary gear assemblies and other transmission parts. It can also damage motor mounts, transmission mounts, and other drive line components. Wait for the engine to drop off fast idle before shifting into gear.
4. Do Not Drive Like You Were On A Drag Strip
Putting the petal to the metal stresses the family car out. If you want to drive like Mario, Cha Cha, or Dale, buy a car designed to be driven that way.
5. Do Not Shift From A Forward Gear Into Reverse, Or From Reverse To A Forward Gear, Without Bringing The Car To A Complete Stop.
Use your brakes and stop completely. Shifting into reverse while your car is still moving in a forward direction, or into drive while moving backwards can have dire consequences. The worse case scenario is that catastrophic transmission failure will occur. The best case scenario is that premature transmission failure will occur.
6. Do Not Try To Free Your Car From Sand Or Snow By Rocking It
Dig yourself out or call for a tow. Both are less costly. Repeatedly shifting from Drive to Reverse and from Reverse to Drive causes the transmission to overheat. Rocking the car to free it is another carry over from the stick shift days.
7. Do Not Put The Transmission Into Gear Before The Engine Reaches Operating Temperature
With the cost of gasoline on the rise, many people are hesitant to burn the gasoline necessary to allow an engine to warm up. Waste it! The gasoline you burn waiting for the engine oil and the transmission to reach operating temperature will cost you less than the cost of premature transmission failure.
8. Do Not Tow Or Allow Your Vehicle To Be Towed With The Drive Wheels On The Ground
Front wheel drive vehicles must be towed with the front wheels off the ground. Rear wheel drive vehicles must be towed with the rear wheels off the ground. All-wheel drive vehicle and vehicles with full-time four-wheel drive must be towed on a flatbed. The improper towing of a car with an automatic transmission can seriously damage the transmission.
9. Do Not Play Doctor
Transmission additives are not the route to go. Additives may make the symptoms disappear but they do not cure the problem that caused the symptoms to appear. Take your car to a transmission specialist at the first sign of a problem.