[Whisper1]

Originally Posted by Zee66

Just picked up 2012 black ZL1 with a 700 HP lingenfelter kit, Its automatic and only has 5000 miles on it. Question, the rearend clunks when taking off sometimes and moans and groans when backing out of driveway. is there a TSB on this condition? Should this be drained and flushed out?

Just corrected the moaning and groaning when cold and turning at low speed. I ordered the correct fluid for the dealer (they did not have but one quart in stock) and carried the TSB as reference. I asked them to just change the fluid at my expense since the noise was not too severe. I noticed on the bill that they had added friction modifier. Incorrect, since the LSA gear oil already has the modifier added. Also noted that 1 quart of gear oil was used - it takes just over two. The manager was very apologetic and drained everything a second time and refilled with 2 quarts of the correct fluid. Noise is gone. I had the problem at purchase (7500 miles) and had it corrected at 10K. The clunking noise is noted in one of the TSB's. Hope you have a good relationship with the dealer since the mods voided the warranty in the eyes of many dealerships - good luck and hope you get the issues resolved.