When I left the dealer with the truck last February, I ended up turning around and bringing it back due to a clunk heard from the rear end during the upshift from 2nd to 3rd gear. My salesman agreed and promptly had the service center order the parts. They ended up changing some gears out in the rear end (over $760 in warranty work), but found it did not solve the clunking problem. They then handed me a bulletin from GM acknowledging the clunk noise stating, "During a 2-3 upshift, the 2-4 band is released and the 3-4 clutch is applied. The timing of this shift can cause a momentary torque reversal of the output shaft that results in a clunk noise." They then go on to say theis can happen as well from a 3-2 downshift, and that the condition may be worse on a 4-wheel drive due to the additional tolerances in the transfer case. But here's what gets me. The last line on the bulletin reads, "This is a normal condition. No repairs should be attempted." I.E. Guess you're just going to have to live with it! Now in a highly competitive market of full size trucks, and being a Chevy guy myself, I was appalled that GM would say in a sense, "It's not our problem!" To their credit my dealer also installed a harness from the alternator to the generator output BAT terminal to try to solve the problem. But this fix is generally used for an issue with the 1-2 shift slipping or vibrating. Apparently there is some electrical feedback from the charging circuit that can cause some interference in the transmission pressure control solenoid. One last ditch effort will be tried tonight by placing in an aftermarket chip which will change the pressure lines and shift points, plus add a few extra horsepower (which every guy would welcome). We'll see, but I have my doubts.
Comparatively, the truck is a great upgrade from the 2000 Z-71 I drove up to 267,000 before trading it in. The combination of the seats being more snug, and the suspension seemingly being tuned for more comfort on the road, aides to not feelings tired and sore at the end of a long day of driving.
I really like the trip computer that gives fuel economy and business vs personal mileage usage.
Another plus that I thought was only available on Denalis and Escalades is the automatic fold-in mirrors that come in handy when pulling the truck in the garage.
Only minor gripe I have is when you turn on the parking lights, the daytime running lights go off, which I think sorta defeats the purpose of being highly visible.
Other than my clunking problem, it is a solid, enjoyable truck.
Had the same problem with 2003 Z71 LT model with clunking on shifting. Sometimes does, sometimes not. First they said was normal "backlash", then replaced 4-wheel drive train. Still the same. Have had the truck 5 years now.
Other than that, no problem. Guess they didn't look at bulletin before changing all that system for 4-wheel drive. Luckily under warranty.
Would like to know if an aftermarket chip changed any of it though?
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