Author Topic: HELP! Leaking Final Drive (Read 1546 times)

danjarrett1 · « **on:** January 02, 2018, 06:41:50 PM »

I have a 1974 Eldorado convertible, affectionately known as â€œCADZILLAâ€ I bought the car a few months ago expecting a few repairs, and so far, everything Iâ€™ve found has not been that much of a surprise. I am struggling with one issue that I cannot find any documentation on. I bought the GM 74â€™ Service manual, ( itâ€™s a well written manual in my opinion) but thereâ€™s very little about the final drive. I have a fair amount of leakage around the whole pumpkin, it may be that the output shaft seals are leaking but itâ€™s hard to know exactly where the leak is because the differential cover is leaking. Here's the dilemma, the previous owner gobbled a ton of sealant on it but I'm not sure that it's right, does anyone know if there is an applicable gasket for the cover or is it sealed only with silicone sealant?

The Tassie Devil(le) · « **Reply #1 on:** January 02, 2018, 06:52:00 PM »

The cover can be sealed with a Silicone, if you don't have a gasket, as there is supposed to be a gasket there. I use Loctite 5900 silicone, as this stuff is also compatible with Auto Trans fluid.

The side seals are replaceable, but one must remove the axles to gain sufficient room to access these.

Bruce.

danjarrett1 · « **Reply #2 on:** January 02, 2018, 07:58:10 PM »

Thanks for the reply, I intended to try to locate a gasket or maybe even a part number from a diagram for a gasket....using correct silicon formed gasket is an option, and in the end, will likely be the solution. Just wondering if anyone I. The Eldo word knows if there was a gasket there when this thing left Detroit!

The Tassie Devil(le) · « **Reply #3 on:** January 02, 2018, 09:06:42 PM »

Yes, there was a gasket.

Bruce.

danjarrett1 · « **Reply #4 on:** January 02, 2018, 10:44:43 PM »

What is the gasket refered to? The only gasket that I can find is the replacement gasket between the final drive and the transmission! I cannot find a reference to a differential cover gasket. Anyone have any idea where to find one? OPGI doesnâ€™t t recognize it, neither does Caddy Daddy. Any other resources I should check??

The Tassie Devil(le) · « **Reply #5 on:** January 02, 2018, 10:57:16 PM »

I too could never find a replacement, but the Shop Manual refers to one as a Seal Cover Gasket.

Plus, the Shop Manual makes note of sending the Third Member back to the Dealer for the Factory to service it. The internals are not designed to be rebuilt by outside shops.

Bruce.

Bob Hoffmann CLC#96 · « **Reply #6 on:** January 02, 2018, 11:13:10 PM »

It's called a Final Drive Cover gasket. Group # 5.399 Part # 231285 in the MPL. Might be available GM or try NAPA.
Bob

kkkaiser · « **Reply #7 on:** January 02, 2018, 11:25:25 PM »

fel pro seems to have a lot of stuff,, gaskets etc,, funny i needed a oil pump gasket, and when i called them, they said they didnt have one, but the DID have one that was included in a package of engine gaskets,, so, i goes you have to be broad with your do yo have questions

danjarrett1 · « **Reply #8 on:** January 02, 2018, 11:29:13 PM »

Thanks, Iâ€™ll try a GM source using the MPL part number.

danjarrett1 · « **Reply #9 on:** January 02, 2018, 11:54:25 PM »

FOUND ONE..... Mahle/Victor Gasket on Amazon. P23883 Axle Housing Cover Gasket is how it is described, $12. Thanks all

"Cadillac Kid" Greg Surfas 15364 · « **Reply #10 on:** January 02, 2018, 11:56:10 PM »

Dan,
I might suggest that before you start chasing leaks, clean the area completelt to bare metal (or paint if it is there) and drive it a couple of blocks. You should then be able to determine the source of any and all leaks.
Greg Surfas

danjarrett1 · « **Reply #11 on:** January 03, 2018, 12:01:39 AM »

Thatâ€™s exactly what my plan is! I intend to clean it thoroughly, Drive it and try to identify the leak. Iâ€™m confident that the cover seal is seeping, my concern is that the drive out put shaft seals are leaking as well..but clean and drive will tell

bcroe · « **Reply #12 on:** January 03, 2018, 12:33:55 AM »

My money says its not the axle seals. Some of the replacements
are not really up to the standard of the originals. Is it gear lube
or trans fluid?

Note also, there is a pair of seals between the trans and the
final drive, and a small vent in the area. Might have a piece
of wire sticking out. Bruce Roe

danjarrett1 · « **Reply #13 on:** January 03, 2018, 12:41:39 AM »

Good suggestions! Iâ€™ll look into those areas. Really need to get is all cleaned up then drive it and see what manifests

Jeff Rose CLC #28373 · « **Reply #14 on:** January 03, 2018, 12:25:52 PM »

Check to be sure that vent isn't plugged. It could be mostly dry but leaking when the pressure builds up.
Jeff

danjarrett1 · « **Reply #15 on:** January 03, 2018, 12:29:07 PM »

YES! A plugged vent will cause the case to be pressurized and blow seals, had that happen on a transmission once!

Bob Hoffmann CLC#96 · « **Reply #16 on:** January 03, 2018, 01:53:31 PM »

Quote from: danjarrett1 on January 02, 2018, 11:54:25 PM

FOUND ONE..... Mahle/Victor Gasket on Amazon. P23883 Axle Housing Cover Gasket is how it is described, $12. Thanks all

Do you have a link??

danjarrett1 · « **Reply #17 on:** January 03, 2018, 01:59:11 PM »

Amazon. Canâ€™t forward the link from here found it on amazon

TJ Hopland · « **Reply #18 on:** January 08, 2018, 09:27:48 AM »

The original gasket is 2 layers and one of the gaskets has a slot in it that is the vent. If the last person just sealed it with sillycone its not vented so when it gets hot it just looks for any place to escape it can find.

fishnjim · « **Reply #19 on:** January 08, 2018, 09:44:01 AM »

If the mileage is high and the bearings and seals are worn, then gaskets won't help (unless it's just the diff cover leaking). Seepage around the pinion seal is a tell tale of gear wear and loss of proper lash.