Warped diff. housing on 98 vert

[MrWizard]

I noticed a small oil leak under the rear of the 98 vert , since we were going in to the dealer for the 60k service in 2 days , we had it checked then , we were informed the leak is caused by a warped half of the diff. housing and the repair includes the new "upgraded" housing half for $635 , has anybody had this before? It seems to me that this must have been a concern to make an "upgrade" , and might fall under defective parts. Any help would be greatly appreciated.

 

[cruzer99]

Call Mark or Terry at Motor Sport Image in Roseville (916-784-2323) before you do anything. If it is what I think it is, it's most likely a seal. MSI specializes in C5's and after you have them do anything you'll never let a dealer touch your car again.


Sorry, had the wrong phone #.

 

[GreyGhost]

???? Warped???
The housing is cast metal. Cast metal does not warp, it can crack or break from an impact. Was your car in an accident?

 

[c4c5specialist]

Hi there,
While it is possible that the flatness of the housing where the sidecover bolts to, the percentage of that is less than 5%.
Honestly, there was a revision of the procedure to repair the leaks on the differential, using a new design seal and anerobic sealant.
I would simply ask how far out the case is warped and of what surface????
This will tell you in 1 min if this is actually the case.
Allthebest, c4c5

 

[tipcapman]

Hi there,
While it is possible that the flatness of the housing where the sidecover bolts to, the percentage of that is less than 5%.
Honestly, there was a revision of the procedure to repair the leaks on the differential, using a new design seal and anerobic sealant.
I would simply ask how far out the case is warped and of what surface????
This will tell you in 1 min if this is actually the case.
Allthebest, c4c5

The question is why does the service bulletin call for sealant...if the housing and cover are correct, the O ring should seal just fine. Something is up....

L

 

[c4c5specialist]

Hi there,
Every surface has a tolerance for flatness in the differential housing. However, the largest reason for the upgraded seal installation is insurance. Technicians are never perfect. I know I have misinstalled seals before, so I personally believe that this is to insure that the seals are installed correctly and the seal sets.
This is only my personal opinion here.
But the revised service procedure works, and it repairs the condition.
Allthebest, c4c5

 

[tipcapman]

Hi there,
Every surface has a tolerance for flatness in the differential housing. However, the largest reason for the upgraded seal installation is insurance. Technicians are never perfect. I know I have misinstalled seals before, so I personally believe that this is to insure that the seals are installed correctly and the seal sets.
This is only my personal opinion here.
But the revised service procedure works, and it repairs the condition.
Allthebest, c4c5

C4C5....

You give yourself far too little credit for your mechanical skills.

And besides, that assembly is designed to be mistake proof, for the production line worker who only has a few seconds to do his job.

I still say something is amiss.... an O ring joint between two machined parts should be very robust and reliable. It was seither deigned (or manufactured) wrong, or it is changing in service. I bet the former is true, and they corrected it in subsequent production.

Has GM added sealant to the production process? I doubt it... and also note the problem only occurs on the left side.

But as you say... if the fix is effective, the point is moot, except for thje people who will experience the leak in the future. But the good news is they get to visit their friendly C5 technician!!!!

By the way... the bulletin was vage with repsct to locating the bead of selant... it was confusing to me, and also noted a caution to keep sealant away from the O ring. Was there a supplmental graphic to clarify that topic?

Regards...

Len

 

[c4c5specialist]

HI there,
First, yes, the sealant has been added to production models, from early production 2k4 through end of production. The bulletin notes that the sealant must be added to the flange area, not the actual sealing surface.
As far as c6, the side covers are redesigned to hold the 2 mounts for the rear diff. So, there in may be the change that is required to hold the leaks to a minimum.
Just remember the actual design of c5 differentials has a roller bearing on the left side where the long driveshaft protrudes through the left side cover. It may be that the force of the torque being transmitted through the cover may have a factor in the leaks.
Also, alot of 'leaks' that I have seen were mostly due to the diff being over filled with lubricant. This would cause fluid to be pushed out of the vent, which is located directly above the left side cover in the case.
Please understand, I am speculating on the actual cause because I do NOT KNOW for sure what exactly the reasoning is. This is strictly from what I as a technician sees in serving Corvette.
Allthebest, c4c5

 

[MrWizard]

Thanx for all the input , I dont understand how the diff. housing , or half of it could be warped....caused by heat and torque ,the thing is not a moving part , it is like saying your front fender warped because it was exposed to the sun , the dealer said the housing part will be replaced with the newer version , btw the car has never been in an accident. I called Chevy to let them know that this is incredible , they said they would consider helping.

 

[tipcapman]

HI there,
First, yes, the sealant has been added to production models, from early production 2k4 through end of production. The bulletin notes that the sealant must be added to the flange area, not the actual sealing surface.
As far as c6, the side covers are redesigned to hold the 2 mounts for the rear diff. So, there in may be the change that is required to hold the leaks to a minimum.
Just remember the actual design of c5 differentials has a roller bearing on the left side where the long driveshaft protrudes through the left side cover. It may be that the force of the torque being transmitted through the cover may have a factor in the leaks.

Allthebest, c4c5

So it sounds like there is a problem they couldn't solve with a simple in line production change. Was there a new design housing produced, as MrWizard alludes to , or just the new shaft seal?

There isn't any torque load going through the housing, it could just be the heat up/cool down cycles that are causing a marginal seal to finally let go.

L

 

[MrWizard]

Update , on this leaking cover , I called Chevrolet customer assistance , stated my case , sent the documentation and they are reimbursing me the $802 I spent to fix this...I am the 3rd owner of this Corvette , and it has 59K miles on it , I will not speak ill of Chevy.