Tranny "clunk"?

[cutntrim]

My new GMC 2500HD started "clunking" when I shift into reverse and back up 20-30ft. Doesn't matter whether it's in 2wd or 4wd. Doesn't do it if I only back up a few feet either. Called the GM dealer and spoke to the "shop foreman" who said he didn't think it would die on me suddenly but to bring it by when the snow ends. We just finished our first go-around plowing, and there's lots more snow to come. After reading Dino's thread about his 4L80E I'm somewhat concerned. My truck has the same transmission and the truck is a 6.0L auto with only 4,800kms. Any ideas?

[urethane dino]

My father in law had an 02 2500 HD and the trans went out at 12000 miles. He never plowed or towed with it. Traded it on an 03 while his truck was on the lift. Good luck I hope it makes it. Oh yeah, it was a reverse clunk that he brought it in for.
Dino

[cutntrim]

Beauty. :rolleyes:

[jbeland]

First, I would like to thank you guys for scaring me. My 2002 does the same thing, but it doesn't sound as bad as cutntrim's. I have been searching other forums and I think (at least hoping) that I just have the normal chevy driveline clunk. It seems that the majority of people are having problems with the front yoke making noise. I am also going to change my rear end fluid to see if maybe that is the problem.
I would like to take my truck in, but I only have one truck and they are showing chances of snow every other day. I have to drive it and wait to see if it gets worse. Hopefully it won't and I can take it in, in the spring.

Jeff

[cutntrim]

My "tranny clunk" has mysteriously disappeared. The second night of plowing for this week's storm it just sorta went away. I was babying it during the night - doing lots of forwards-only circle plowing and only backing up a few feet at a time when possible.

The "clunk" had been quite audibly noticeable when reversing 20-30 feet, but then I'd back up 60-70 feet before hearing it. The sound was fainter as well. By the end of the night it had just gone away altogether. Beats me :beatsme .

I was all set to schedule it for a service visit to the dealership but I'm gonna keep my fingers crossed and not take it in unless the "clunk" returns...

:burnout

[BRL]

"I was all set to schedule it for a service visit to the dealership but I'm gonna keep my fingers crossed and not take it in unless the "clunk" returns... "

I don't agree with this solution. If I have drive train concerns or noises, I get them checked out. Better to hear it was nothing than have it fall apart in the middle of a big snow because something wasn't adjusted, repaired or replaced, when I heard or felt something wrong. Just did this with a "clunk" I was hearing right when putting my Blazer into reverse. I'm not sure if it was already checked out yet, or if its on the list of things to be done to it as soon as we get a break in the weather & can get it back into the mechanic's place for some other stuff. I'm thinking something may have been done about it, because I don't remember hearing the noise this last storm. I haven't seen the invoice yet to know exactly what got done & what didn't when they had it last week for some stuff. But my point is, as soon as I heard a potential problem, I scheduled it to be checked out because I do not know how to fix them.

[Earthscapes]

took my 03' in for this problem last week.... seems that the splines on the driveshaft are NOT greasable. They pulled the drive shaft out lubed it up and put it back in. Took care of the problem. I have racked up another 1000 miles mostly plowing since last week and it has not come back...the noise that is...

Seems when the grease runs out the splines lock (seize) up....another wonderfull design. 04 is on the way...someone buy my 03' lol :D

[wyldman]

I agree with Earthscapes.Lube the slip yoke and it should go away.Common problem on GM's for years,and GM has a special grease for it.The dealer should have picked up on this right away when you mentioned it.

[JustUsDe]

Originally posted by cutntrim
My new GMC 2500HD started "clunking" when I shift into reverse and back up 20-30ft. Doesn't matter whether it's in 2wd or 4wd. Doesn't do it if I only back up a few feet either. Called the GM dealer and spoke to the "shop foreman" who said he didn't think it would die on me suddenly but to bring it by when the snow ends. We just finished our first go-around plowing, and there's lots more snow to come. After reading Dino's thread about his 4L80E I'm somewhat concerned. My truck has the same transmission and the truck is a 6.0L auto with only 4,800kms. Any ideas?


My 2003 2500hd started making same noise 2 weeks ago. I havent had time to get it to the dealer. I only have 9,000 miles on it.

Ray

[JustUsDe]

Originally posted by cutntrim
My "tranny clunk" has mysteriously disappeared. The second night of plowing for this week's storm it just sorta went away. I was babying it during the night - doing lots of forwards-only circle plowing and only backing up a few feet at a time when possible.

The "clunk" had been quite audibly noticeable when reversing 20-30 feet, but then I'd back up 60-70 feet before hearing it. The sound was fainter as well. By the end of the night it had just gone away altogether. Beats me :beatsme .

...

:burnout
Mine went away too. I was trying to duplicate the noise to a friend and it wouldnt do it. Yesturday I scored a pallet of salt and have it in the truck and the noise came back. It seams to only do it when I have a load in the back. No load in the back no noise.
Maybe next week I can get it to the dealer.
Ray

[cutntrim]

Ray - my "noise" returned the other day when I was loaded up and out salting. Called the dealer and mentioned what the other guys said about greasing the slip-yoke. Took it in this morning to get it looked at.

I'll post again when I get it back.

[cutntrim]

Picked up the truck from dealer this afternoon. Said they "could not replicate the clunk noise". So, they said that they couldn't find anything wrong with it, and to swing in there if it's making the same noise when I'm loaded up with plow and full salter.

That scenario is likely for tomorrow, so I'll stop in there if it starts clunkin' again...

[JustUsDe]

I talked to the dealer this morning. I gave him my long list and I have an appointment this Thursday. He said to leave the salt in the truck if I think the weight is an issue. I will let you know what happens.

Ray

[cutntrim]

Well, I did go back in...but there weren't any transmission mechanics in yet. By the time I was back in the area, I'd spread all my salt and the "clunk" was gone.

They may say that is "normal", but I don't remember any clunk noises when backing up with my '89's or '85 GM's. 'Course I wasn't running around with a yard-and-a-half of salt in the back either.

[JustUsDe]

I dropped the truck off Wed afternoon with my long list of repairs needed. I couldnt get it to make the clunk noise. They said when they look at it today they will check it out and see if there is any tsbs on the problem. I told them that one of the members here said their dealer greased the front yoke and that seemed to take care of it. He said they have done that to a few and it has worked but it was on trucks that clunked all the time not intermittantly. I also told them not to make my truck undriveable without contacting me since we have a slight chance of snow later today. It would be my luck they would tear it apart and the storm decides to come up north further. I will keep you updated on what happens.

Ray

[JustUsDe]

Here is a short story on my great experience with my small list of issues with my truck. Well, According to the dealer I don't have any issues or I'm nuts or maybe hearing and seeing things.

Problem 1: Passenger wiper nut keeps getting loose and stops working.
Customer: Please just dont tighten it because it will work loose I already tightened it about a dozen times.
Dealer: We tightened the nut and put lock-tite on it. Please make sure you have no snow build up on the wipers before you turn them on. NO CHARGE
Customer reply: My truck is on the road before snow even starts that is not the problem. The problem develops long after the wipers have been on for a while, even in rain only.
Problem 2: Amp gauge goes up to about 16 and if truck isnt run for a couples of days slow start.
Customer: The truck used to only charge up to 14.
Dealer: No draws found. Tested charging system. No problems found. NO CHARGE
Problem 3: Passenger headlight out.
Dealer: Replaced. NO CHARGE
Problem 4: Power steering noisey. When at idle and turning wheel to the left somes real hard to turn.
Customer: It doesnt do it all the time, it does it with or with out the plow on. But more with plow on it. The pump is noisey all the time.
Dealer: Pump has normal noise, can not duplicate problem. NO CHARGE
Customer: Please do a LOF.
Dealer: NO CHARGE
Problem 5: When backing up around 20 to 30 feet get a clunk noise.
Customer: This happens in 2 or 4 wheel drive. It doesnt happen all the time. It seems it does it more when the truck has a load in the bed.
Dealer: Bring it in with a load if you feel this would help us find the problem.
Customer: I will bring it in with a load in the bed. Also I was talking to some people on a message board that has the same problem. One wrote his dealer lubed the yolk and the problem went away.
Dealer: We have done the same thing but it was on trucks that made the noise all the time. We will check to see if there are any TSB on the truck.
Dealer: We could not duplicate the problem. Rear springs were real dry, we greased them, maybe that was the noise. Why did you bring the truck in with 1500lbs of salt in the back? NO CHARGE
Customer: I brought it in loaded because on the phone you told me to. Thanks for the LOF and the headlight. I'm sure I will be back thanks for keeping my truck for 3 days.


Looks like I didnt get much done. Does it?
Ray