The seal on the output drive shaft at the back end of a transmission can fail over time and start leaking. You can tell if the transmission fluid is leaking from this seal in a couple of ways. The first way is you'll see transmission fluid dripping and/or pooling on the driveway about halfway down the length of your vehicle. The other way is to look under the vehicle where the transmission connects to the back drive shaft and look at the connection point. If you see transmission fluid leaking out of the connection, you know the seal is bad. You'll need to replace the seal connecting the drive shaft to the transmission to stop the leak. Here is how you can replace the output drive shaft seal on a transmission.
Step One: Remove Drive Shaft
The drive shaft takes the energy generated from the transmission and transfers that energy to the back wheels on rear wheel drive vehicles – this is what makes your rear tires spin around when the vehicle is in gear.
The drive shaft has to be disconnected so you can pull the head of it out of the back end of the transmission. Here is how to remove the drive shaft:
- Put some wood blocks underneath the drive shaft part going into the transmission to hold it up before you disconnect it from the differential on the other end of the drive shaft. The differential moves up and down and twists to ensure your back wheels stay on the road when going over bumps.
- Remove the four bolts connecting the drive shaft to the differential. The bolts can be hard to loosen. If you have this problem, grab a rubber mallet and tap on the end of a flat wrench to pound the bolts loose.
- Remove the bolts connecting the drive shaft to the transmission. This end of the drive shaft is called a slip yoke.
- Slide the head of the drive shaft out of the transmission and gently set it on the ground.
- Use a flathead screwdriver to force the seal out of the back end of the transmission. Be careful not to damage the threads on the gear in the end of the transmission.
Install New Seal
Take your new output drive shaft seal, and cover it with the same type of fluid you are using in your transmission.
Take the seal and place it into the end of the transmission. You may have to use a small ball peen hammer to carefully tap it in place.
Slide the slip yoke end of the drive shaft back onto the end of the transmission and bolt it back in place. Then, reconnect the drive shaft to the differential to complete the repair job.
If this task seems to difficult for you to handle on your own, then hire a repair service like A Transmissions to do it for you.