When pulling a trailer yesterday I noticed my 05 lly did not want to pull it in overdrive (lost speed when shifted to overdrive) but 5 minutes before that it was pulling it no problem. so i just stayed in the gas just enough to keep it from downshifting and all of the sudden it was like someone flipped a switch and it started pulling great again. I do have a Predator running factory tune with speedo adjust for 285's. I checked for codes and it is showing P0101 I cleared the code and fired it back and the code popped up again and i did not even rev it up. Dealer sayes they will look at it next week. It does do it all the time it was just more noticeble under a load.

See this link as I had answered ont eh other page in regards to Allison's statements for towing with 285's on the truck and it's shifting problems.

http://www.allisontransmission.com/service/faq/index.jsp?CategoryID=11


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