REAR DIFF FLUID SERVICE - DO 8 FIGURE 8's TSB - CHATTER

[ZO6 Bryan]

Originally Posted by Sven59

Plus upgraded half shafts, basically a completely different rear end. It may function the same, but so do most engines and they all have different problems. The point I have been trying to make is this is a very common issue, I have had it twice, plus I have had the backlash issue. The TSB is specific to the ZL1 and is more than just figure eights, there is a copy of the TSB somewhere here. Basically if you have a ZL1 and it makes noise from the rear when you are slowly turning, especially in colder temps, you need the TSB. If your ZL1's rear makes sound when decelerating, chances are the backlash is off and the ring and pinion will need to be replaced. This is also a common issue. If you search through the forum this topic has been heavily talked about.

And I am well aware of the multiple threads on this subject. But everything you stated applies to ANY limited slip rear diff. Where have you been the last 5 decades?

[Sven59]

Why is there a TSB specific to the ZL1 then, if they were all the same it would apply to all.

[Stephen12ZL1]

the clutch pack in the ZL1 rear is more aggressive than the SS. Maybe the friction material on the disc surface or the spring pressure is greater in the ZL1 posi unit? No doubt it works well and is very tough. Just use the correct GM LS gear oil and definitely change it after break in at 1500 miles. Some unlucky souls have had true issues with improper setup, backlash, bearings, etc...but these problems are rare.

[ZO6 Bryan]

Originally Posted by Sven59

Why is there a TSB specific to the ZL1 then, if they were all the same it would apply to all.

Blah Blah TSB blah.
Clutch based limited slips have been around since the 50's. There is nothing special about the one in the ZL1. Just because GM wrote a TSB doesn't mean it's a new problem. How many diffs have you rebuilt? And actually set pinion depth and backlash? They all make noise if not set up correctly.

The T2R is the diff they should have used for the ZL1.

[ZO6 Bryan]

Originally Posted by Sven59

Why is there a TSB specific to the ZL1 then, if they were all the same it would apply to all.

Specific to the ZL1? I don't think so. Count the hundreds of TSB's
https://www.google.com/webhp?sourcei...B+differential

[winterboy8]

Originally Posted by Stephen12ZL1

the clutch pack in the ZL1 rear is more aggressive than the SS. Maybe the friction material on the disc surface or the spring pressure is greater in the ZL1 posi unit? No doubt it works well and is very tough. Just use the correct GM LS gear oil and definitely change it after break in at 1500 miles. Some unlucky souls have had true issues with improper setup, backlash, bearings, etc...but these problems are rare.

So I don't have my manual in front of me, hence the question. Is changing the rear diff fluid part of the 1500 mile break-in service? I literally just called my dealer to have my 1500 service done this Friday. Is there more than an oil change I need ensure is completed by the dealer?

[1troyd23]

How do you look up all the GM TSBs ? Is there a website ?

[JWR046]

Originally Posted by Stephen12ZL1

the clutch pack in the ZL1 rear is more aggressive than the SS. Maybe the friction material on the disc surface or the spring pressure is greater in the ZL1 posi unit? No doubt it works well and is very tough. Just use the correct GM LS gear oil and definitely change it after break in at 1500 miles. Some unlucky souls have had true issues with improper setup, backlash, bearings, etc...but these problems are rare.

Funny I had my rear end oil changed at 1500 miles just because. 400 miles later it started whining when cold. I took it back to dealer and they performed the TSB. I did all the driving on the roads but they dropped the oil and did the figure 8's. All good now. I should get my $88 back for changing it at 1500. :(

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.

[Sven59]

GM: WHEN MAKING LOW SPEED TURNS THERE MAY BE A CHATTER NOISE FROM THE REAR OF THE VEHICLE. THERE IS A SLIP/STICK OF THE CLUTCH PLATES. THE 2010-2014 CAMARO EXCLUDING ZL1. *RM UPDATED 07/31/2013 *JS

This one excludes the ZL1.

[Sven59]

I am trying to get full copies of both TSBs. One is for the ZL1, the other excludes the ZL1. I will post as soon as I get them.

[Sven59]

Both TSBs have the #PIP5097 but have different NHTSA numbers 10052061 and 10038346.

[Sven59]

#PIP5097: ZL1 Rear Differential Moan Noise On Turns - (Mar 6, 2013)
Subject: ZL1 Rear Differential Moan Noise On Turns

Models: 2012-2013 Chevrolet Camaro ZL1

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.

With original lube in axle, conduct Freeway Speeds for 10 miles to warm up lube.
Immediately drain original lube and refill with fresh lube.
In parking lot lock steering to the right, and then execute 5 Full Circles at (5-10 mph).
In parking lot lock steering to the left, and then execute 5 Full Circles at (5-10 mph).
Perform 4 Figure 8’s at (5-10 mph).
Freeway Speeds for 20 miles until operating temperature is achieved.
In parking lot lock steering to the right, and then execute 5 Full Circles at (5-10 mph).
In parking lot lock steering to the left, and then execute 5 Full Circles at (5-10 mph).
Perform 4 Figure 8’s at (5-10 mph).
Immediately drain current lube in axle and refill with fresh lube.
Perform Steps 3 thru 9 again.
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

[nsane]

Thanks for posting the TSB!