Purchased a used Silverado with 68,500 miles on it. On delivery noticed a clunk on braking and a severe clunk and slingshot feeling on acceleration. After a lot of investigation found the problem was due to axle wrap. The rear springs are very long and relatively soft for a cushy ride, and the axle had a 2 inch lift block (4x4 model). A bad combination that just invites axle wrap.

I left the car in park and laid on the ground underneath it, and rolled the tire up and back. I could see the axle pinion rotating up and down, confirming the diagnosis.

I purchased 440 lb full length helper springs and installed them. The lift from the helper springs was 2", so I was able to remove the lift block. Ride height remained exactly the same.

The ride is a little stiffer but now I have zero clunk and a much more direct feel on braking and acceleration. Problem solved. Axle wrap is a serious issue and shortens the life of u joints and can waste the back of the transfer case. Chevy blew it on this one, engineering the springs a bit better is all they need to do. Do an internet search for "axle wrap", it is a common problem in the off-road crowd especially when trucks are lifted the cheap way with lift blocks instead of correctly arched springs.

I purchased my 2003 Silverado 4 WD PU new. At about 18000 miles it developed a clunking noise in the drive train when upshifting from 2nd to 3rd gear and when downshifting from 3rd to 2nd. It is an automatic transmission. Chevrolet said this is normal which is a crock as we all know. The service bullitin stated it has to do with the 2nd to 3rd gear clutch pack but that it is normal and will not get worse or create any other drive train issues. Well knowing this was a crock but the fact they would not do anything about it other than extend my warranty to 7 years or 75,000 miles, I now have excessive slop in the rear end which only makes the clunking noise worse and you can sometimes feel it in other gears when you accelerate or let off the gas. I beleive this clunking has damaged the rear differential most likely the spider gears in the posi unit. This means a new posi, installation kit and labor costs. If this is the case I am going to install a high performance posi unit (Eaton or Auburn Gear). This repair is going to cost me about $650-$700. What a way for Chevrolet to really piss of a loyal, die hard Bowtie fan.

I bought this truck used. Took it in under the 90 day/3,000mi warranty and had them look at it. They looked (superficially), but took nothing apart and said the noise is normal. The transfer case is clunking and moving a lot when accelerating at lower speeds. Stationary, with a foot on the brake, shifting through the gears it makes a loud click/clank sound. The noise is coming from the opposite end of the transfer case from the 4WD. The dealer (Wissler Motors in Mount Joy, PA) won't fix the problem or acknowledge there is a problem. My wife and kids (and I) are going to get whiplash soon.

I bought a used 2003 Z71 Silverado from the dealer in December of 2007. In april of 2008 i was backing out of my drive way and heard a clunk and the sound of grinding metal. I took my truck to a local garage where the mechanic told me i shredded my spider gears and the chunk of my differential would probably have to be replaced. I then went to the Chevy dealership and they said ive they drove it they concluded that nothing was wrong with my truck. I went back to our local garage and had the problem fixed. I sent chevy the photos of the shredded spider gears to see if they would cover some of the cost. It was a waste of time! I am beginning to question if i am going to stay loyal to Chevy in the future....