How to Investigate Transmission Problems

Your car's transmission is probably the most complex system in the whole vehicle and comes under the most pressure. Not surprisingly, therefore, it can cause issues over time, especially if you haven't kept up with the overall maintenance schedule. Because the transmission system is made up of so many different components it can be challenging to determine where that strange sound is coming from and what part actually needs attention. How can you start to figure out what's going wrong?


In an automatic transmission, if you notice a slight hesitation when you change from park to drive this is an indication that the clutch may need to be adjusted or replaced.

Clunking Noise When Shifting?

If there is a "clunking" noise when shifting gears then this could be an internal differential issue if it appears to be coming from beneath the car, or it could be constant velocity joints if the noise appears to be coming more from the periphery.

Signs of Leakage?

Sometimes the symptoms will not be audible, but visual. If you notice a bright red deposit on your driveway in the morning have a closer inspection. If the consistency is somewhat clear and it has a sweet smell then this indicates that it's working properly, but you do need to locate and fix the hole! If, however, the fluid is a darker red appearance and has a burnt smell then you will need to change the fluid and book the car in for a service to determine if any repairs are also required. When you check the transmission fluid note that it is not like engine oil as it doesn't "burn" over time. Any low-level indicates a leakage somewhere.

Won't Move When In Gear?

What happens if the car won't more when you put it into gear? Firstly, you need to check to see the fluid is at the proper level, but you also need to determine whether the linkage between the gear shifts and the clutch may need to be adjusted. In modern cars this can also be an issue with the computer. One way to "reboot" the system is to disconnect the battery and let it stand for a while. This may rectify the problem.

Noisy if Stationary?

If your transmission is noisy when stationary this could mean that the internal bearings are worn, or you need to change the reverse outlet gear. It could also mean that the primary gear teeth are reaching the end of their natural life.

Slipping Out Of Gear?

If you notice that the car is slipping out of gear, or changing into an inappropriate gear from time to time this is of course a serious risk to safety. The likely cause here is that the linkage that holds the gears is wearing out.

Gathering the Information

All this information could be valuable to a professional mechanic as they help you to diagnose and then fix issues with your transmission, as well as provide other essential services like differential repair.