Replacing 430 leaking rear seal?

[68RIVGS]

Question - To replace the rear crank seal on a 2nd generation Riviera 430, is it necessary to pull the engine and tranny as a unit, 

or can it be accomplished by just removing the ST400 tranny and the oil pan ?

As I recall,  the engine mounts need to be loosened to raise the engine to gain clearance so the pan will clear the frame cross member for removal,

but the engine is also supported by the rear tranny mount, so it may be a lot easier to pull both as a unit ?

[KongaMan]

You can buy a lot of oil for the hassle of pulling that engine and tranny.

[rocky5517]

Mine loses about a tablespoon a month but if I push it hard, it slows down to next to nothing. Nothing that 25 cents of kitty litter can;t handle. When we had th trans out, this is what we saw; can't say the effort to pull the engine, or chance breaking the exhaust manifold bolts, is worth it. Let;s hear what the experts have to say.

[RoadShark]

I had my 430 out to replace the manifolds.  The oil pan bolts were amazingly loose.  It might help some...

[JZRIV]

You can pull just the engine. Undo the converter/flywheel bolts and the transmission can stay put when pulling engine. Yes the engine won't slide forward much to uncouple from the trans before the oil pan hits the frame. Probably easier to unbolt trans at rear mount, block the pan, and slide it back a couple inches allowing the engine to be raised. With engine out replace the front trans shaft seal before going back together. Jim Weise owner and founder of V8Buick.com and expert 455 engine builder has a pinned thread on rear main seal replacement to guarantee no leaks. Its specifically states for the 455 but the 430 should be same. When you read the steps taken by Jim to insure no leaks, the only way to accomplish that is with the engine on a stand. http://www.v8buick.com/index.php?threads/bop-455-rear-seal-install-step-by-step.301130/

 

 

 

 

Edited December 12, 2017 by JZRIV (see edit history)

[RivNut]

Russ Martin has a method of removing the old rope seal from the nailhead and installing a new neoprene seal.  Perhaps the same process can be used on the big block series motors.  You have to have the pan off to do it.  On a 1st gen Riviera, that means pulls or lift the engine.  I don't know if you can get the pan off of a 2nd gen with the engine in place.  

 

See if you think it's possible.

 

http://centervilleautorepair.com/tech-info/install-rubber-rear-main-seal-special-instructions

[68RIVGS]

Thanks Ed - unfortunately, the easiest way to get the pan off is to pull the engine - see Jason's post #5.