Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
It does sound normal, things drained out and had to be refilled when running so it does that and loads up against the park pawl.
I Would get it hot, make sure the fluid is good and drive it to see if this continues.
I Will see if I can get the bulletin that outlines ths .
WE DROVE THE TRUCK ABOUT SEVEN OR EIGHT MILES BEFORE WE NOTICED THIS PROBLEM. ARE WE STILL ON TRACK FOR YOUR ANSWER? HOW FAR DO WE NEED TO DRIVE IT? WE HAVE THIS TRUCK FOR SALE AND HAVE A PROSPECTIVE BUYER. CAN WE GET A SERVICE BULLETIN THAT COVERS THIS SITUATION?
A bulletin only has info, but I am looking
This bulletin is being revised to add the 2010-2012 model years. Please discard Corporate Bulletin Number 08-07-30-026 (Section 07 - Transmission/Transaxle).
Some vehicles may rock or move slightly forward or rearward while in park at start up after cold soak. This condition may be accompanied by a clunk noise. This is a slight movement that is more often seen visually, rather than felt, when viewed from the outside and using the auto-start feature, if equipped.
This slight movement is due to the residual transmission fluid in the clutch packs that creates a partial apply on start up. This movement is stopped by the parking pawl and/or transmission fluid exhausting completely from the clutch packs.
This slight movement has no adverse affects on the transmission and no repair should be attempted. This condition is normal. This can be verified by comparing with another identically built vehicle under the same cold conditions.
To prevent this condition from occurring, the parking brake should be utilized as per the Owner's Manual recommendations anytime the vehicle is parked.
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IF THIS DOES NOT CORRECT CAN I GET BACK TO YOU FOR MORE INFO? HOW DO I PRINT THIS CONVERSATION.
COpy and paste to text or word to print
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Did that work?
THIS INFORMATION SEEMED TO WORK. WE DROVE THE TRUCK FOR 25 MILES THOUGH. WHERE CAN I GO TO FIND BULLETIN # 08-07-30-026A SO THAT I CAN PRINT A COPY TO SHOW MY PROSPECTIVE BUYER?
Attachments are only available to registered users.
This PI was superseded to update model years. Please discard PIP3161D.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Customer may comment that trucks equipped with the Allison LCT1000 transmission may experience a clunk type noise on start up with the vehicle in park. Customers may also experience a clunk noise when shifting into park from reverse or a drive range or when shifting from Park into Reverse. The condition may be intermittent. Customers may also comment that when shifting into and out of park repeatedly without releasing the brake pedal the clunk into Park or into Reverse will become more frequent and repeatable.
The noise is a result of internal transmission clutch drag which is sufficient enough to load the output planetary carrier. The resultant load on the output planetary carrier can result in park pawl gear tooth impact against the park pawl and cause the clunk noise. The magnitude of the noise is dependent on the position of the park pawl gear relative to the park pawl.
This condition is considered to be an operating characteristic of the Allison LCT1000 transmission. Repairs or replacement of the transmission will not correct this condition.
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.