View Single Post
Old 07-24-2013, 05:51 PM   #1
Sven59
HAMMER PILOT
 
Sven59's Avatar
 
Drives: 13 ZL1#182, 85 CJ7, 16 Silverado
Join Date: Nov 2011
Location: Tucson AZ
Posts: 4,388
ZL1 rearend noise bulletin

Here is an excerpt from the bulletin.


The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern
Some customers may comment on a moan noise from the rear axle during cold start turning maneuvers. In some instances the noise has been described as coming from the front of the vehicle. The noise may start to be noticed as the vehicle accumulates over 3,000 miles.
Recommendation/Instructions
Note: Steps 2 – 9 MUST be performed two (2) times for a total drain and fill of three (3) times to have this procedure be effective.
1. With original lube in axle, conduct Freeway Speeds for 10 miles to warm up lube.
2. Immediately drain original lube and refill with fresh lube.
3. In parking lot lock steering to the right, and then execute 5 Full Circles at (5-10 mph).
4. In parking lot lock steering to the left, and then execute 5 Full Circles at (5-10 mph).
5. Perform 4 Figure 8’s at (5-10 mph).
6. Freeway Speeds for 20 miles until operating temperature is achieved.
7. In parking lot lock steering to the right, and then execute 5 Full Circles at (5-10 mph).
8. In parking lot lock steering to the left, and then execute 5 Full Circles at (5-10 mph).
9. Perform 4 Figure 8’s at (5-10 mph).
10. Immediately drain current lube in axle and refill with fresh lube.
11. Perform Steps 3 thru 9 again.
12. Immediately drain current lube in axle and refill with fresh lube.
This procedure is only to be used for the condition listed above. During regular maintenance, the fluid only needs to be changed one time. The maintenance schedule can be found in the owner’s manual on pages 11-5 and 11-7. For regular service the fluid is changed at 45,000 miles or 72,000 Km and for severe service the fluid needs to be changed every 15,000 miles or 24,000 KM.
Oil Dextron LS Gear 75w90: US - 88862624 2.43 Qt.; Canada - 88862625 2.3L
Warranty Information
For vehicles repaired under warranty use:
Labor Operation
Description
Labor Time
F9744*
Road Test, Drain, and Refill Axle 3 Times
2.6 Hours
* This is a unique labor operation for bulletin use only. It will not be published in the Labor Time Guide.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

© 2013 General Motors. All rights reserved.
Bottom of Form
__________________
"DO YOU WANT ME TO PUT THE HAMMER DOWN?"
Sven59 is offline   Reply With Quote