Circumstances, fate, maintenance, lubrication, heat, and build quality all play a part in how long your car's transmission will last. While you cannot control fate or the build quality of the tranny, you can have something to do with the rest. If you want your transmission to last as long as possible, here are a few things you need to make sure you do and some that you need to avoid.

Maintenance

Make sure you read the owner's manual that came with your vehicle and follow all maintenance schedules for the transmission. Maintenance will include checking fluid levels, topping them off when necessary, and changing the fluid and filter at the recommended intervals.

Lubrication

Lubrication involves the fluids the different parts of the transmission need. An important thing to know about transmission fluid is that not all types are the same even if they are the same grade. Each type has a different amount of slip to it. This will affect how things feel when gears change.

Heat

Without the fluids, the transmission parts would rub against each other and create heat. If there is enough heat it can cause parts to warp so they do not work together correctly. Different fluids will transfer heat differently. If the one you use does not transfer the heat efficiently it will shorten the lifespan of the tranny.

Circumstances

How hard you run the vehicle is one of the circumstances that will affect the life of the transmission. This can include high speed, pulling a trailer, or not using the proper gear while going uphill. Do not force your vehicle to do more than it is capable of doing. Listen to the motor and cut back on the speed or change to a lower gear if it is starting to sound stressed. If you are towing a trailer or other vehicle, do not go over the recommended two weight.

Most transmission work will require someone with experience in servicing them. It may require heavy equipment to pull the tranny out of the engine compartment. It is up to you to check oil levels and pay attention to how your vehicle is shifting gears (whether it is a manual or automatic transmission). At the first sign of trouble, take the vehicle in for transmission service. It will save you a lot of money if the tranny can be repaired instead of waiting until it is not working at all and needs to be replaced.