99 GmC Sierra

[lonewolf21]

When my truck shifts into gear, there is a loud "clunk". When shifting from second to third gear, the loud "clunk" is heard again. When the passing gear kicks in, the loud "clunk' can sometimes be heard. When I questioned my dealer about this noise a year ago, he said it was your typical GMC drive train noise. Any suggestions?

[GMMerlin]

Check the universal joints

[lonewolf21]

I have a 99 GMC Sierra SLE 4X4 Extended Cab, with a 4800 SFI V8. This unit comes with Autotrac Automatic 4WD. When shifting from park to drive or reverse, there is a loud "clunk". Same when the transmission just shifts from second to third. I can't remember if it "clunks" from first to second gear. I noticed the last time I pulled out to pass a vehicle, the "clunk" was there when the passing gear kicked in. I just had all the universal joints replaced, and the "clunk" is still there. Suggestions from several arm chair mechanics range from checking out the rear axle, to replacing the transfer case.

[intimida]

most likely the cause of your clunk is lack of lubrication on the slip yoke.thats the part that slides into the transfer case it usually gets stuck and when the drivetrain shifts it clunks pull out the driveshaft and lubricate the outside of the slipyoke generously and reinstall and roadtest.

[CaptnSam]

I have a 2003 GMC, K1500 with about 2000K on the clock. When I brake to a stop and then take my foot off the brake I get the "Clunk". I have found a TSB No. 01-0417-004 dated October 2001 that appears to identify my problem and explain the fix. That is a replacement nickel-plated driveshaft slip yoke, but my question is...does this TSB apply to my 2003?

I would like to have all my ducks in line and in step before I go back to my GMC dealer to "Discuss" this issue...

CaptnSam

[intimida]

have you taken it to your local dealer and if so what was there answer?i have performed that tsb on some pretty picky customers and then had to explain and drive the truck with them to assure they were satisfied because some driveline clunk is normal due to the backlash in the differentials. the lubrication i do instead of replacing the yoke usually works better than replacing it.because you are dealing with an aluminum driveshaft i have seen some guys really mess them up.the clunk i am referring to actually feels like someone hit you from behind when releasing the brake to accellerate from a stop. gm has issued an information tsb to explain the normal characteristics of clunk it has to do with backlash and is normal. ok to answer your question yes the new style yoke will work with your truck,

[CaptnSam]

I have taken it into the dealer and they kept the truck for two days...their answer was "..it is just the body settling" and "New truck noises"? I have driven GMCs for the thirty years and just traded in my '92 with 218,000 on the clock. I have never had one clunk like this and it does feel like some one is using a sledge hammer on diff. The noise is annoying, too!

I will return to the dealer and suggest he look at the slip yoke. Thanks for the info...

[intimida]

quick question does it sound like oil canning,and can you feel it by the drivers feet area? i had a couple 03 sierra's were the left front wheel well under the hood was contacting the firewall or as we call it a bulkhead.sorry to hear of your unpleasant dealer experiece sounds like a blowoff too me. i'm located at a dealer in philadelphia and do all the heavy and medium duty trucks along with all the other vehicles. if i can help in any way metro pontiac gmc buick philadelphia automall

[CaptnSam]

No, it is definitely coming from the rear. I feel it from the brake pedal and spinal column as though someone were hitting the diff with a hammer. It feels and sounds like a "Clunk". It happens 90% of the time when I stop and release the brake to start up again. Sometimes when I am about to come to a stop, sometimes turning sharp to right or left, and occasionally when the tranny is shifting. This is 2003, four wheel drive, short bed, so I expect a certain amount of bumps and groans, but this seems to be getting worse.

I live in Fredericksburg, VA, so a trip to Philly is not just up the road...besides I would have to drive through DC and that is not fun!!! Sorry,

Thanks again for the info...

[CaptnSam]

Well, I made a second trip to the dealer with the TSB in hand and “Suggested” they take another look at the problem. Their response was the TSB was for 99 thru 02 and that the 03 came off the production line with the replacement slip yoke…whatever? The bottom line is they lubed the slip yoke and miraculously all is better…for now!

Thanks, again for your help…

[madmalibu]

My 2000 had the same problem. The dealer did the same thing - lube the yoke. Which is just a temporary fix, as soon as the grease wears off it will happen again. Every owner of a similar model has the same problem, they should be replacing these things. If you hear of any kind of recall, let me know.

[chuckyknuckles]

Had same problem at 21,000 miles. They replaced with supposed high tech blue fluid in transfer case. Got paperwork from dealership. Corporate bullietin #99-04-21-001 Dated april 99.

[ricpdjrr]

What ever happend to the grease fitting on the slip yolk?? They must be saving millions not installing that any more

[roysie]

My 99 gmc started "clunking" awhile back(still under warranty) , Dealer replaced transfer case fluid with synthetic...problem gone.