charliet615

1993 LT1, I need to change the rear seal. I've read many post about some units require that you count the amount the turns of the pinion nut, mark location and return to the exact location. Some threads say that on the late 90's, that this is not needed because of crush seals or washers are not in the 93 model? Which is correct and which fluid should i use to refill the rear end. Any help is appreciated. TX, Charlie

C409

…. The C4 diff's use a solid spacer and shims to set pinion bearing pre-load … instead of a crush sleeve … So , change your seal and tighten it up (don't overdo it) just tight … Most synthetic gear oils have the Posi clutch additive … I prefer to use 85w140 mineral oil with GM friction modifier additive …..

ctmccloskey

Hello there C409!

What causes the seals to go bad in the first place? Heat? Loose bearing clearances or is it just age?

Are they drying out or is the shaft inside moving around enough to stress the seal?

I remember changing the rear main oil seal on my first Car and as soon as I put ten miles the new seal it was leaking again, it turned out the crankshaft bearings were so worn that the crankshaft was moving around forcing a leak.

Sorry to bug you with these questions but I am trying to understand HOW it wears out. Fortunately my differentials are not leaking on either of my Corvettes.
Thanks for taking the time to help some of us come up to speed!

Are you using a solid rear axle on the red Corvette in your Avatar? I would love to have a picture like that of one of my cars but I fear I would have to spend a lot of time and money to make it capable of pulling the wheels off the ground without breaking something. Maybe I should just "photo-shop" my car into a picture...probably the closest I will ever come to lifting the front end off the ground.

Thanks for your time and advice!
Chris a.k.a. ctmccloskey

C409

….. Why do seals fail ? … I don't know … why does beer go flat ? why are women and doctors always late ? why do people drive corvettes when a camry will do ? … I just don't know ! …..

….. My 'vette still has the IRS … Dana 44 with a Newman Car Creations housing , custom spool , and 4.33 gears … everything else back there is stock-ish (poly bushings) including the shocks …..

Gibbles

I did mine by counting the threads and marking the exact location of the bolt.
It worked great, no issues.

I did the same thing with my S10, new seal and inner and outer pinion bearing (all new bearings and seals), i put over 100k since then with 0 issues.

Truck drives smoother than it did @40k miles.