Driveline Noise

mawint · December 20, 2012

Alright truck nuts (not the ones you hang from the hitch) my truck seems to be making a weird noise all of a sudden. Long story so I will use the tl;dr version.

Snowed a week ago so we decided to take the truck more places with it being four wheel drive and all. First time I have used it all year, now the truck seems to be making a clunk on take off. Feels like it is directly below my feet, isn't very audible from the outside.

Any ideas? It is driving me insane.

Side note: u-joints have been replaced on both axles. Weird observation though, the guy said the front driveline was about to fall out. Made me think the last guy who had it drove it around in four wheel drive all the time.

I guess not really tl;dr but the more info helps I guess.

black128412 · December 20, 2012

first you of a shop of choice, flush and fill front diff. you may find that when you pull drain plug out it will come with a ton of metal i.e. junk front diff. if ok make sure that fwd is dissengaging also in 04 i think they were all active transfer cases so if front diff ok flush n fill transfer case(use gm fluid) and do it againin 3-5kmiles last is poss wheel bearing going bad and cold plus xtra work may have finally done 1 in...good luck

8.1HD/ALLISON · December 20, 2012

+1 on checking/changing fluids. What U joints have been replaced? The driveshafts? Front/ rear? The axles don't have u joints. Could also be the rear driveshaft slip yoke sticking. They had some bullitins on that, not sure what years. If you have rear driveshaft out, smear a lil antiseize on the inside of the slip yoke.

mawint · December 20, 2012

first you of a shop of choice, flush and fill front diff. you may find that when you pull drain plug out it will come with a ton of metal i.e. junk front diff. if ok make sure that fwd is dissengaging also in 04 i think they were all active transfer cases so if front diff ok flush n fill transfer case(use gm fluid) and do it againin 3-5kmiles last is poss wheel bearing going bad and cold plus xtra work may have finally done 1 in...good luck

I will look into this, I haven't thought of changing it since I haven't seen any leaks. 4wd does disengage and reengage like it should, tested it on a little bit of ice and snow yesterday with just a small take off. Once the wheels spun as they should I let up, 4wd grabbed like it should also.

+1 on checking/changing fluids. What U joints have been replaced? The driveshafts? Front/ rear? The axles don't have u joints. Could also be the rear driveshaft slip yoke sticking. They had some bullitins on that, not sure what years. If you have rear driveshaft out, smear a lil antiseize on the inside of the slip yoke.

Sorry, the drive shaft u-joints is what was replaced, both front and rear. The driveshaft would clunk going into gear and were replaced with spyders (sp?) u-joints. Since they found the front one was worse then the back, I had them replace all four. I suppose it could be the rear yoke sticking because it is colder tightening up clearances, it just feels like it's coming from the front though like the front driveshaft is sticking.

Best way I can describe it is it feels like I have something in the bed sliding around (I don't, I checked, saddle bags too) and on take off smacks the tailgate or something but comes from the front of the truck.

Spurshot · December 20, 2012

I'd lube the rear driveshaft slip yoke (with the right lube). That's a 15 minute job. That needs to be done anyway.

8.1HD/ALLISON · December 20, 2012

I'd lube the rear driveshaft slip yoke (with the right lube). That's a 15 minute job. That needs to be done anyway.

What is the right lube? Antiseize is what we used at the dealer. Haven't heard otherwise.

BlackZ71Silverado · December 21, 2012

GM is using transmission fluid on the newer truck, do not use grease or anti seize.

The clunk you describe has been a known issue for quite some time now and there is an updated slip yoke to cure that issue.

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dannyg2006 · December 29, 2012

I've had the same problem with my '99. After replacing the slip yoke, u-joints, and a GM reman transfer case, still has the clunking sound but only when you put it in reverse in 2wd. I already spent over $2,000 and still have the same problem. Now the dealer is saying that it's in the rear end. So good luck on yours.