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HELP: Leaking Diff !

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4.2K views 16 replies 15 participants last post by  FourG63 97GST  
#1 ·
I have just noticed a small leak under my 02 Z. :jawdrop:

Crawled under to find the driver side of the diff leaking. I have not yet had time to lift the car, clean it, and see exactly where it is coming from. However, it appears to be either, or both, of the driver side cover gasket or the seal for the driver side half shaft. I will assume that my 7/100 extended GM warranty will cover this repair. It is the first real problem I have had with an otherwise outstanding car.:(

I have strong preference to fully diagnose a problem before bringing it to back to a dealer for repair. Has anyone else had this problem? What other things should I inspect or look for to fully understand the problem? :eek2: :blush:

As always, I appreciate any input ! :cheers:
 
#2 ·
This might help you.

Vehicle: All Technical Service Bulletins Drivetrain - Rear Differential Fluid Leak

Bulletin No.: 03-04-20-006 Date: November 18, 2003 TECHNICAL
Subject:Fluid Leak at Rear Axle (Replace Left Differential Side Cover 0-Ring and Left Axle Shaft Seal, Add Sealant to Side Cover Flange)

Models:1997-2004 Chevrolet Corvette

Condition: Some customers may comment on fluid leaking from the rear axle.

Correction: Verify that the fluid leak is rear axle fluid, not transmission fluid. Replace the left differential side cover 0-ring and left axle shaft seal. Engineering has recommended that sealant be applied to the side cover prior to installation. Use the appropriate service procedure and part numbers listed below.

Service Procedure (Corvette)
1. Raise and support the vehicle.
2. Remove the left rear tire and wheel assembly.
3. Install J 33432-A Transverse Spring Compressor to the rear transverse spring and compress the spring.
4. Disconnect the electrical connector from the left wheel speed sensor.
5. Disconnect the electronic suspension control (ESC) position sensor link, if equipped.
6. Disconnect the shock absorber solenoid electrical connector, if equipped.
7. Remove the outer tie rod end nut
8. Disconnect the outer tie rod end stud from the rear suspension knuckle.
9. Disconnect the park brake cable from the park brake apply lever and bracket.
10. Remove the bolts securing the upper control arms to the frame.
11. Remove the spindle nut retaining the rear wheel axle shaft to the hub.
12. Rotate the suspension knuckle until the axle shaft clears the hub,
13. Release and remove the rear wheel axle shaft from the differential.
14. Remove the left muffler.
15. Drain the rear differential fluid.
16. Remove the retaining bolts and the damper/tuned absorber from the differential.
17. Loosen the nut retaining the transmission to the transmission LH mounting stud.
18. Install a second nut onto the stud.
19. Remove the stud from the differential cover.
20. Clean any dirt or debris from around the differential cover.
21. Remove the bolts retaining the differential cover.
22. Remove the differential cover from the differential.
23. Remove and discard the 0-ring seal and the axle seal from the differential cover.
24. Clean the 0-ring sealing surface on the differential cover and the differential housing.
25. Install new 0-ring, P/N 89047953, to the differential cover.
26. Apply a continuous 3 mm (0.125 in) bead of sealant, P/N 1052942 (Canadian P/N 10953466), or equivalent, to the cover flange.
27. Apply sealant around the bolt holes. Keep sealant away from the 0-ring.
28. Install the differential cover to the differential.
29. Install the differential cover retaining bolts. Tighten Tighten the bolts to 28 N.m (20 Ib ft).
30. Clean the excess sealant from the left cover/housing splitline.
31. Using two nuts installed on the stud, install the transmission mounting stud to the differential cover. Tighten Tighten the stud to 42 N.m (31 Ib ft).
32. Remove the second nut from the transmission mounting stud.
33. Tighten the nut retaining the transmission to the transmission LH mounting stud. Tighten Tighten the nut to 50 N.m (37 Ib ft).
34. Install the damper/tuned absorber and bolts to the differential. Tighten Tighten the bolts to 25 N.m (18 Ib ft).
35. Install the new axle seal, PN 88996703, into the differential cover using J 46405.
36. Install the left muffler.
3 7. Install the rear wheel axle shaft to the differential.
38. Install the spindle nut retaining the rear wheel axle shaft to the hub. Tighten Tighten the spindle nuts to 160 N.m (118 Ib ft).
39. Install the bolts securing the upper control arms to the frame. Tighten Tighten the upper control arm bolts to 110 N.m (81 Ib ft).
40. Connect the park brake cable to the park brake apply lever and bracket.
41. Connect the outer tie rod end stud to the rear suspension knuckle.
42. Install the outer tie rod end nut. Tighten
- Tighten the outer tie rod end nut to 20 N.m (15 Ib ft) to seat the outer tie rod stud.
- Turn the nut additional 160 degrees.
- Check the outer tie rod end nut for a minimum torque of 45 N.m (33 Ib ft).
43. Connect the shock absorber solenoid electrical connector, if equipped.
44. Connect the electronic suspension control (ESC) position sensor link, if equipped.
45. Connect the electrical connector to the left wheel speed sensor.
46. Remove J 33432-A Transverse Spring Compressor from the rear transverse spring.
47. Install the left rear tire and wheel assembly.
48. Refill the rear differential fluid.
49. Lower the vehicle.
 
#6 ·
Same here .. common problem, easily fixed by dealer.

Les

jub jub said:
It's pretty straight forward. I've had the leak and replaced the seal. It's been holding up pretty well.
 
#7 ·
Excellent information.
I just discovered the very same leak described here.
Glad to know its an easy fix.
Does the O-ring fail or is it undersized or what is the cause for the leaK?
 
#9 ·
Make sure that it's not leaking from the "vent" and not the seal after you get it repaired and continues to leak. They did mine 3 times. The first visit I trusted them to do a good job and let them keep it over night. When I went to pick it up they put over 30 miles (in the rain) on my Z. I discussed my unhappiness with the shop manager. He explained to me that the first seal he installed was not the proper size even thou the part number was the same as what was called for. ( lets call it a mfr defect) They installed another one (still on 1st visit) It started leaking again with in a week. I took it back but this time waited for it and took my camera and a copy of the TSB with me hoping to follow them step by step to ensure it was installed properly. No such luck, they didn't allow me into the shop. I had to settle for a veiw outside the fence. From my point of veiw I didn't see them use a torque wrench. I told them I was coming along on the test run. The tech. didn't even drive 2 miles. Which makes me wonder about what really went on during the first visit.

Sorry for the rant but I thought it's important to inform you guy's of what could happen if you decide to take it to a dealer's shop.
My advice is to find a good trust worthy mechanic and take your parts and the TSB with you and follow it step by step.
 
#10 ·
If you need to leave the car at the dealer for any length of time, take the odometer reading and make sure both the service rep and the tech are aware that you have the reading recorded. I have read some horror stories about the techs joy riding, wrecking and/or totalling out the customers car.
 
#11 · (Edited)
I just had my drivers side diff seal replaced under warranty this week. It started to drip a drop every night after parking it so it wasnt too bad, but I had to get the clutch master cylinder replaced also (very common to start leaking above left foot inside) so they did them both.

FYI: The mileage was the same when I picked it up so no joy rides in my car, but im curious how they knew they fixedthe leak if no test drive.
 
#14 ·
I feel your pain. My 2000 has the same leak, and I think it might be BOTH sides, but since it is out of warranty, I just refill it every 3 months. Almost like a oil change. yeah, it sucks, but sure beats the $800 - $1000 to repair. And, at the rate I am going, a little inconvience goes a long way.

Fluid: approx. $10.00 x 4 times a year = $40.00 x 20 years = $800.00. Now, if I keep the car for 20 years, I break even. If I sell it at 19 years, I still saved some money! :cheers: But it is a PITA seeing that spot in the driveway!!!
 
#15 ·
Leaking Diff

My '02 ZO6 driver side diff was leaking. Dealer fixed it under the service bulletin. Repair was done about a year ago. I noticed last week a small leak, now I just returned from a PDA event at Watkins. Ran the car pretty hard. Took it back and they noticed it was coming from the vent, but they put some dye in to see where it was coming from in case it was leaking again. But the dealers are pretty helpful in repairing this problem. Unless you have the tools and know how let them do it.
 
#16 ·
Had this service done last week with two weeks left on the warranty. So far so good.

In my experience you should call around to the dealers, find one with a dedicated Vette tech. Around here Dayton Chevy has two, and when I was in there, they had 6 vettes in for service, 4 of them Z06's. You are unlikely to have problems when they work on them all the time.
 
#17 ·
notice mine on my 02 leaks a lil also. I work at the dealer so had the tranny guy look at it, he said its common and the new will probably leak as much.

I checked the level and cleaned it up. and i'll keep an eye on it.
when its start dripping on the floor is when you should be worried.