Changing rear main seal

[Yamaha74]

I have a 1983 Chevy 4x4 3/4 ton with a 350 and a TH400 tranny. What do I have to do to change the rear main seal in the motor? Is there a lower and upper seal that needs to be changed? Aren't these seals like a half moon?

[Russell]

It isn't half bad, esspecially on a 3/4 ton 4x4.

You'll need to drop the pan (thats where the 3/4 ton 4x4 part is advantegous, no need to jack the engine up to get the pan off) remove the rear main, peel the old lower seal out of the cap, then use it to push the upper seal out far enough to grab with a pair of pliers. Install is the opposite of removal, except I'd suggest you smear some oil on them where they silde on the crank to help them slide in.

This would also be a good time to check on your main bearing, since you are right there, if its good, go ahead and button her back together, making sure that you torque everything correctly.

Also, consider getting a single peice silicone pan gasket while you have your pan off. They are simply awesome, and are re-useable