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C5 Rear Differential Leak Repair

C5 Rear Differential (Output Shaft Seal) Repair

While CA Corvette Customs focuses primarily on the design and fabrication of C5 double din bezels and custom car audio installation, with repair genius and corvette enthusiast Ray Enriques at the helm, it’s only a matter of time before a common corvette repair is tackled.   One common problem is a leak on the output shaft seal of the rear differential on the driver’s side.  General Motors has known about this issue and has appropriately documented it in one of their TSBs (Technical Service Bulletins), number 03-04-20-002.  Presented here is a documentary of our work on this repair.  One theme throughout that should be noted is that the goal here was NOT a “minimalist” approach.  As with all of our products and services, our approach is strongly perfection oriented with attention to detail and absence of short cuts.

Want to have this repair done right & avoid dealer prices?

After having reviewed this project, if you’re in Southern California and dealing with this problem on your C5 Corvette, we can do this repair for you.   We charge $575 and the repair takes about a day.  This charge covers our labor only and does not include the needed parts that we would ask you to acquire in advance from your local GM dealer and auto-parts store:

Mobil 1 Synthetic Gear Lubricant 75W-90 LS, 1 quart container (The LS is important, it means Limited Slip Additive is already in oil… none to add separately!)

GM Gasket Maker sealant, GM part #1052943  (this is a red thick liquid)

Shaft seal – GM part # 88996703

Differential cover O-Rings - part # not available, consult your GM dealer.


The Repair…

First, let's see one of the tell tale signs of a leaking output shaft seal.  Pictured is the view of from the rear of the suspension cradle.  Notice the nice black gunk concentrated along the left half side of the cradle.


The process starts by jacking her up and removing the rear tires,



Being a stickler to detail and wanting the job done right, Ray washes as much grease off the cradle as possible, but will do more later,




The Rear control arms and shock come off,

Removing bolts to lower rear suspension cradle,

In preparation for the cradle removal, the catted X-pipe, Mid-pipes and tunnel plate are removed.  Further, the tranny is supported,



Removal of the rear suspension cradle,





This is a good time to get a closer look at the left side of the differential...





Also, observe how the gear oil and dirt, make a nice sludge spray on the left side of the tranny,


It’s interesting to compare the right side of the differential,

With the cradle completely removed, here is another look,


OK, now its time for a good bath with degreaser and then water, the differential first,




Time to clean the cradle, but to really appreciate this, let's get a good look at the sludge,



Alright, bath time...



Ah, much better...


The final clean up is to remove sludge of transmission shown earlier,



With all these preliminaries done, now the actual repair can be performed… surgery is prepped and started on the left side rear differential,



The red GM Gasket Maker (sealant) #1052943 is applied, the a new O-ring installed, and the left cover plate put back on,







Now, attention is turned to the right side differential, similar process as before,




Sorry... we didn't get picture so the shaft seal removal and replacement but here are pictures of the old shaft seals.  A seal puller made removal of these a piece of cake,



From here on out, the process is everything in reverse.  However, here are a few more pictures

Placing the rear cradle back into position,



Putting the cradle back on is by far the most challenging part of this job. 6 bolts are to be lined up with the heavy suspension cradle “floating” on a jack,


Once the repair is completed, here is a nice clean rear now!