when i have my truck in 4 wheel drive on the highway, it gets this weird vibration at about 60-70 mph upon acceleration, any ideas what this could be?

Mine is doing the exact same thing, can anyone help give us some clues???

I am hoping you guys are joking, but with the lack of any emoticons I can't tell. If you're truly having this issue, then I am going to say that it is because the truck was never meant to be driven that fast in 4X4, let alone on pavement.

I am hoping you guys are joking, but with the lack of any emoticons I can't tell. If you're truly having this issue, then I am going to say that it is because the truck was never meant to be driven that fast in 4X4, let alone on pavement.

:exactly:

I agree, unless, there's snow or ice on the hyway, even then, going that fast in 4x4 yur lucky that's all you get. OBTW, When the vibration quits, let us all know what it was!

You make it sound like we are hiway maniacs, I noticed when traveling the interstate with some mixed hiway road conditions, patchy ice then pavement etc. Here in Montana if you go slower the truckers run you of the road. Besides, my other 03 never had this vibration, something is not right reguardless.

You make it sound like we are hiway maniacs, I noticed when traveling the interstate with some mixed hiway road conditions, patchy ice then pavement etc. Here in Montana if you go slower the truckers run you of the road. Besides, my other 03 never had this vibration, something is not right reguardless.
I have run on highways (patchy ice) many times in 4x4. thats what it's for. Guess I'm a maniac too!
Have never noticed any vibration.
suppose it could be the transfer case (pump rubbing) that I've read about on here ? Jim

I take my truck up to about 105mph,in 4x4, on pavement all the time.

ya ive had many 4x4's and this is the only one that does this... its not normal by any means

yea even had mine at 120 in 4x4 .. on pavement, no vibrations here? Check you axel boots make sure they are not torn. There is a groan noiose, but no vibration. I know the groan is normal .. had that on every 4x4 I have had.

My 01 GMC has been doing that for a while - 70 mph 4x4 and noticable vibration. Now it makes chunking sounds in front under load:( The vibration could be out of balance drive shaft or worn ujoints, bearing in the TC or diff? I hope the chunking is the actuator intermitently disengageing.
My other 4x4s were smooth, especially the Toyota - 90+ mph for 4 hours steady.

Found my problem after checking out more posts here;

Transfer case pump rub:( :mad: . nice little hole and no fluid.
Will do the belzona/JB weld fix. Just need to find a warm place, -35 deg wind chill outside. I wonder if I should file a report to GM?This should be a recall item judging by the amount of trucks with this problem.

Definitely should be a recall item. We should get on GM to make it a recall item, I'll help out, let me know what to do, where to send my letter, make my phone call, whatever.

Found my problem after checking out more posts here;

Transfer case pump rub:( :mad: . nice little hole and no fluid.
Will do the belzona/JB weld fix. Just need to find a warm place, -35 deg wind chill outside. I wonder if I should file a report to GM?This should be a recall item judging by the amount of trucks with this problem.

You should flush out the case and see how much metal you get. Your case is probably toast.

Just finished patching the T-case. Letting it cure inside for awhile, its -30 deg outside. I flushed the case and not much came out:) . A very small amount of sludge with a bit of metalic flakes. I've seen worse on an oil change - not the Dmax though. I`ll see how it goes on the ride home from work this morning.

Just finished patching the T-case. Letting it cure inside for awhile, its -30 deg outside. I flushed the case and not much came out:) . A very small amount of sludge with a bit of metalic flakes. I've seen worse on an oil change - not the Dmax though. I`ll see how it goes on the ride home from work this morning.

That sounds encouraging, good luck.

So far so good. The patch is holding on nicely and the vibration and clunk are gone. Still a bit noisey when engaging into 4x4.
I hope this will last until spring. Then I will have to decide what to do to fix the problem. I might try Dmaxalitechs pump cover, and weld up the hole. I would prefer a new case half but GM wants $800+.