Transmission problems fall into two very similar categories:
- Won't go.
- Won't go smoothly
These two groups of problems are caused by the same faults in your transmission, so whichever your car is doing, the following applies.
Is your fluid level correct?
It's important to check your transmission fluid at least twice a year. Not only can a low fluid level cause your car to shift poorly, it can eventually lead to transmission damage, and a costly repair. If your car seems to be losing fluid on a regular basis, you may have a leak.
Is your transmission leaking?
Checking for leaks isn't as trying as it may seem. The transmission is a closed system, so there are only a few places that can spring a leak. Unless it's been changed to a non-dyed fluid, your car will have red transmission fluid. Here are a few places to check for leaks:
- At the filler tube base.
- At the drain hole underneath the transmission.
- Between the transmission and the engine.
- At the selector shaft - the rod that connects your gear shift to the transmission.
- Speed sensor mounting point. This will either be your cable screwing into the transmission housing or an electronic sensor bolted to the housing.
- The radiator. If your car has a transmission cooler, it's possible that a leak will cause transmission fluid to leak into the radiator fluid. They don't mix well, so you'll see it floating around in there.
Is your filter clogged?
Your transmission's filter is vital to its performance. If you haven't replaced your filter in a while (or ever for a lot of us), be sure to do this before you start talking about rebuilds or replacements.