UPDATE: Well, with the new switch the problem has returned, intermittently. That is the problem, the Chev dealership service manager says since the "service engine soon" light goes out after the truck is warmed up he must wait until the light is on when his technician reads the computer, or they can do nothing. The problem occurs when the truck sits for over 4 days in a cold, humid climate, and I can't let the dealer have the truck to just sit for 4 or more days for the light to come on.
April 11, 06 UPDATE: Well, my truck is at the GMC dealership, the Chevy dealer did not have a certified Allison AT tech. Now they say the drain-back valve in the front pump is defective and must be replaced. The AT, and TC must be removed to access the front pump and replace the valve.Thank goodness GM is performing the work under warranty, because they know this is another problem with the Allison AT and had issued a TSB detailing the fix.
Last edited by Ray,IN; 04-11-2006 at 07:47 PM.