GM PARTS MANAGER

I posted earlier in this thread, get the truck on a hoist and have a close look at the spring packs. mine had between 1/8 and 1\4" of lateral movement that was clearly visible and would cause a "clunk/thump" when backing up in a left or right turn, bumps or no bumps. We tried everything before replacing the leafs, a GM engineer came to pick them up for further inspection. this was a little over a month ago, no more noises and no bulletin or service measure issued yet.

I just had our guys install the pro Comp 2.5" levelling kit in my 2014 1500 double cab 4x4. prior to install the front measured 36.5" and the rear was dead on 39". Installed measures 39" on all four corners with stock 18" wheels and tires. The kit I purchased on Amazon for $165.00(187.00 to my door), labour to install and align was 2.0 hrs. @ $130.00/hr. flat rate. The truck rides great, a little tighter in the front end, no unwanted noises, headlights will need to be adjusted. Tire sizing is next up.

Correct, any grease or lube will be temporary, the bulletin states that it will have to be re applied, the real issue here is the lateral movement of the leaves within the pack. Hopefully GM gives us an updated spring and corrects the problem.

I had this same issue with my 2014 Silverado 4x4 double cab from day one, most noticeable backing up while turning left/right. Spare was tight, exhaust wasn't knocking anywhere, took it into our shop and had a couple of Techs ride with me without telling them what to listen for and they too heard the clunk/bang/thump. We packed the leaf springs with grease as per an older bulletin, noise was still there. TAC suggested replacing the rear shocks which we did, noise was still there. We went over all cab/bed/suspension bolts and nuts, the noise was still there. We put the "ears" on and drove about but got nothing helpful. I had another Tech look at the truck without filling him in on what had been done, he went over all mount/suspension bolts and found the rear leafs were 1/8 to 1/4 of an inch out of alignment laterally(the grease was disturbed), we put a few large hose clamps around the leaf packs and drove the truck, NO MORE NOISE. Got the ok from TAC and replaced both rear leaf springs. We have submitted a P.I report to GM and had a field engineer from Oshawa pick up the springs for inspection, he told me he had seen this on older trucks but this was a first for him on the 2014/2015s. If you experience this type of noise from the rear of your truck have a close look at the leaf alignment.