[MR4WD]

I've got a 2003 Duramax that just hit 44493 KM and it gets it's share of 4wd time. The weather up here has been pretty bad, and the truck has got just too much torque and spins out every where. GMC, extended Cab, Short Box, Allison, push button t-case etc...

The problem seems to lie on the front driveshaft or transfer case. When it's in 4wd at highway speeds (70km/h and up) it seems to vibrate and resonate in the cab. It sounds almost like a growl? I realize that this is not a finely tuned Ferrari I'm driving and that it's a 2500HD, but I can drive my 91 fullsize blazer or a 99 crew cab ford in 4wd at 140k no problems at all. This truck has never been off road per se, so I wouldn't think the driveshaft is bent or anything like that?

I'm not an expert on GMC front ends, but I'm under the impression that the driveshaft is always spinning at the same rate as the rear, and that there is some sort of central axle disconnect? There's no hint of any problem in 2wd. Even though it's still under warranty I'm not quite ready to take it to the dealership and let those clowns tear into just yet, as that may open up another barrel of monkeys with their seeming inexperience on these trucks. I was hoping to get some possible background information, or maybe somebody can relay a similar problem and fix they've had with their truck.

 

[smurfsdad]

I'm suprised you dont hear the same kind of growl in your Ford, is the Ford a F250 or 350 as my 350 growls and all the F250-350's i have driven did so.

 

[Black Dog]

My '01 2500HD Dmax does the same thing, and I have seen plenty of complaints on the web also. I also put 100,000 miles on an '88 half ton Chevy, and plenty of miles on older solid axle stuff, and you could run them all at 70 in 4WD with no vibes at all. The only difference I see on the new trucks is that they used a slip yoke on the front shaft. I think that makes the front shaft wobble slightly at higher rpm under load. I doubt you will get any satisfaction from the dealer. I am just going to live with it, but it may be worse on some trucks.

 

[The Original Diesel]

My 02 does the same thing. Dealer said it "preformed as designed" and sent me on my way. At certain speeds mine will vibrate the crap out of the cab.

I am not quite sure where it is comming from and I don't use 4x all that much so I have never looked into it.......

If you figure something out let us know...........