With a properly working main shaft bearing, your car's transmission main shaft is able to smoothly rotate as you tackle difficult roads and challenging driving conditions. However, just like any kind of automotive bearing, this component will eventually show signs of wear and tear. Once this bearing loses its pre-loading capabilities, it's time to install a new one. Here's what you need to do: (Instructions below serve as a general guide and may not be applicable to your specific vehicle.)
- Drain pan
- Short socket extension
- Socket and socket wench
- Floor jack and jack stands
- Rubber mallet
- Bearing grease
- Transmission jack
Step 1: Jack up your car.
Jack up each frame section that's behind each front wheel. Make sure there's enough space around the transmission. Place the jack stand under each side of the vehicle, and lower your car onto the stand. It's best to have someone assist you when doing this installation job because handling the transmission system can be quite tricky.
Step 2: Unbolt the drive shaft.
Using a wrench, disconnect the shaft from the transmission. Make sure to place a drain pan underneath to catch leaks.
Step 3: Disconnect transmission attachments.
A variety of components are attached to the transmission. Make sure to remove these parts to get access to the transmission. Remove cooling lines with a wrench, pull off electrical wires, and loosen retaining bolts if your car's throttle valve cable and speedometer are connected to the transmission assembly.
Step 4: Remove the inspection plate and torque converter.
With a socket and socket wrench, disconnect the inspection plate by loosening the bolts. Once this plate is removed, you can now access the torque converter. Depending on your car make and model, you might only be able to access one bolt at a time. Through the inspection plate opening, unbolt the converter. You might also need a buddy to crank the engine as you remove each bolt.
Step 5: Unbolt the starter and shifter linkage.
Using a socket extension and a socket wrench, remove the starter by disconnecting the bolts that link the starter housing to the engine. Then disconnect the shifter linkage with a wrench, making sure that you've taken note of the linkage set-up for easier reinstallation later on.
Step 6: Remove the transmission from the engine.
Jack up the transmission using a transmission jack, and unbolt the assembly from the engine. Together with a buddy, loosen the transmission by moving it side to side until the main shaft is exposed.
Step 7: Uninstall the busted main shaft bearing.
Once the main shaft is exposed, unbolt the shaft retainer. You'll now be able to see the main shaft bearing. Remove this bearing with a screwdriver and get rid of the old seal.
Step 8: Install the new bearing.
Apply enough grease on the new bearing and insert it onto the main shaft assembly together with the new shims and seal. Use a rubber mallet to tap it in place.
Step 9: Reinstall the transmission assembly.
Start by bolting the main shaft retainer in place. Then bolt back the transmission into the engine. Then reinstall all the other parts you've removed in order to access the bearing. These include shifter linkage, starter, torque converter, inspection plate, and the various transmission attachments.
Don't forget to take your vehicle for a test drive to ensure that the new bearing is installed properly.