Oldssupreme

Hello. Can anyone explain the proper procedure for removing and replacing the rear tail seal for the TH350 trans? Thanks!
Chris

joe_padavano

Remove the driveshaft
Pry out the old seal with a seal puller
Install the new seal with a seal driver or correct diameter piece of pipe
Install the driveshaft

olds 307 and 403

Be aware that if the rear seal is leaking, quite often the bushing is worn and needs replaced at the same time.

droldsmorland

Careful that the seal removal tool doesn't gouge the tail case seal surface when your prying out the old seal. That will cause a leak. Clean tail case with brake cleaner. Remove any burrs. Apply a THIN film of RTV to either the case or the OD of the seal. Drive it in equally so as not to distort the seal. Oh and palm or finger in (apply) Vaseline on the back side of the seal. This helps keep the tension spring in place when you slip the slip yoke back in....slathered with ATF before insertion of course. Check the slip yoke for grooves and burrs as well. Do not use grease on the back side of the seal.

Oldssupreme

Much appreciated everyone! I'm sure I'll be back with more questions as soon as I get into it.
Chris