silverado clunking noise when rear wheels spin

jdekod · January 13, 2017

I have a 2014 Silverado 1500 Crew Cab LT 4x4

i was pulling out into traffic with fast acceleration. I had the truck in 2H. The pavement was wet, maybe a little icy. My rear tires spun and i heard a rapid clunking noise. It clunked 4 or 5 times during acceleration. When i got home i tried to duplicate the problem. I could not duplicate it on the ice or dirt road, but could on dry, semi wet pavement. It sounds like the noise is from the front driverside wheel (i could be wrong). I thought maybe it is stabilitrac kicking in so i turned stabilitrac off and could not reproduce the noise.

My two uneducated speculations are, 1. the stabilitrac is applying my brake on the front driverside wheel, or 2. the hub is trying to lock on the front wheel when my rear wheels started spinning faster. This went away when i turned stabilitrac off, so i dont know if there is a correlation between stabilitrac and auto 4x4. Like i said though, i had it in 2H but thought maybe it wasnt working correctly.

How do i approach the dealer... Ask them to do a burn out and see what im talking about? i wasnt abusing the vehicle when it happened but thats the only way to reproduce the problem...

cbrsilv15 · January 13, 2017

It's your G80 locking rear differential. It's normal. Doing what it's supposed to do.

scott19677 · January 13, 2017

First thing to do is read the owners manual. Not trying to be a smart ass but that's what everyone told me a few years ago also when I had similar questions. Lol And they were correct.

Second. I wouldn't even mention the phrase "burn out" anywhere near the service dept because it will make on to your paperwork and if by some small chance you have a legitimate problem the dealer will only blame you.

It sounds like you were driving in pretty mixed conditions with it being wet, possible ice, and I know my Z71 has the G80 and it makes a lot of noise at times and is bad about having some wheel hop when the roads are wet/dry. But I think you could probably tell the difference between that and something "clunking" and coming from the front in 2 hi is what is weird. Does everything work good in 4auto? That is what I use when driving in sketchy conditions. Were you turning sharply when pulling out? Reason I ask is that on mine sometimes when turning sharply and applying the throttle it kinda pushes or scrubs (for lack of a better term) the front tire(s) and activates the nannies and it gives a strange feeling/sound from the front. I guess it comes down to was it a "good" clunk or a " bad" clunk? Lol

If everything is working fine in auto4 and it only does it 2 hi I wouldn't think you have anything to worry about. Probably just the characteristics of the rear end or some of the electronic tc/stabilitrac. Hope you find out what it was. Keep us posted.

jdekod · January 13, 2017

cbrsilv15, i understand that i may feel and hear my differential lock, but i swear this is coming from the front end. i guess i could be wrong but i will play with it some more to be sure. i also tried to produce this with my work truck this morning, 2015 sierra 1500, but it did not create the same issue. the work truck does have stabilitrac but is not 4 wheel drive.

scott, Yes it was slippery conditions. i have not tried it in 4auto.

Z45 · January 13, 2017

G80

Principles of Operation

¨ Wheel speed difference (left to right) in excess of 100 RPM will cause a flyweight mechanism to open and catch a latching bracket.

¨ The stopped flyweight will trigger a self-energizing clutch system, which results in the cam plate ramping against a side gear.

¨ Ramping increases until both axles turn at the same speed (full lock), which prevents further wheel slip.

¨ At speeds above 20MPH, the latching bracket swings away from the governor and prevents lockup from occurring.