Please need help. 02 6.0 shaking violently

[02GMC2500HD]

So at about 60 mph i start to get a bit of a shake, nothing else i can notice up to there. As speed increases so does the shake until about 75 mph it feels like Im on washboard gravel, then at 80 mph, nothing wrong, drives smooth. Im not sure where to start on this one, maybe front driveshaft? anyone else have this kind of issue before? Ive had the tires balanced by a friend who says they are perfect.

 

[02GMC2500HD]

also to add, it doesnt matter how much weight I have on/in it

 

[Mebes]

Nothing noticable around 45mph?

I have thrown weights off 2 different driveshafts over the years and the 70 to 80 range sounds about right but If I recall correctly there was some small vibrations under 50 as well.

Did this just start recently?
If it did take a look at your rear driveshaft looking for clean or less rusted spots where the weight would have been.

You can also attach a hose clamp (to act as a weight) to the drive shaft about 2/3rds of the way back and see if the problem changes in speed range or intensity.
This will hopefully confirm that the driveshaft is the problem.

On my first car that did this back in the 80's I pulled the driveshaft and had it re-balanced.

On my last one ~2010 I just moved the clamp around the shaft until I found the sweet spot and left it there until I sold the truck a couple of years ago.

Edit: http://www.demandaam.com/technical-support/aam-technical-tips/driveshaft-balancing

 

[BossPlow2010]

Alignment

Yes had the problem in a ford about 8 years ago just as you described it, was like 17° off

 

[Philbilly2]

Is the shake in the steering wheel or felt in the body of the truck?

First idea would be to move your tires around. A broken belt on a tire will balance on a machine, but give you hell if it is on the front of the truck.

 

[Randall Ave]

Do you feel it in the steering wheel, or the floor

 

[Ajlawn1]

Ahhhh yes the Ford death wobble... Mine was track bar but can be tie rods, tire balance, alignment... Need to get under there and see if anything is loose first...

 

[Avalanche 2500]

ck. tires, warn on one side / a bubble/broken belt. Ck. lug nuts for tightness. Just a esay way to start. Lift frt. end up
off the ground, ck. for tire wobble n/s. e/w. look for play in tie rod while moving/wheel bearing noise. Get a crowbar under tire/ground
lift up/down look for movement @ balljoints ??

 

[m_ice]

Ahhhh yes the Ford death wobble... Mine was track bar but can be tie rods, tire balance, alignment... Need to get under there and see if anything is loose first...

I thought that was a thing on the old Dodges???
Either way I'm glad the OP keep going faster and put closure to the shaking stopping at 80 mph...

 

[m_ice]

I'm going with something tire related as it goes away with the speedo pegged and the centrifical force balancing it out

 

[Ajlawn1]

I'm going with something tire related as it goes away with the speedo pegged and the centrifical force balancing it out

Mine was the same, certain mph is when it did it... You either needed to slow down or speed up... But yes I would slow down... Felt like it was going to shake the truck apart... Suprised some windows didn't shatter tbh...

 

[LapeerLandscape]

Just another (hurry up I have a problem) and never to return.

 

[EWSplow]

Ahhhh yes the Ford death wobble... Mine was track bar but can be tie rods, tire balance, alignment... Need to get under there and see if anything is loose first...

Some jeeps had the death wobble. Usually the sway bar. A new stabilizer helped.
Makes for interesting driving. Floor it on the highway to get above shake speed and have to brake to get back below.

 

[02GMC2500HD]

Thanks for all the replies guys and sorry @LapeerLandscape I work saturdays. 100% confirmed tires are good, and its most steering components are good (little slop in the gearbox maybe 2 degrees of play) its a whole truck shake, So Im about to go pull my front driveshaft out before i take it to the store for massive hose clamps(aluminum DS) just for kicks to see if its the front
Thanks for the replies guys ive been mulling over this. Ill probably update this tomorrow!

 

[02GMC2500HD]

Update. Pulled front driveshaft and did a "fast" run to the parts store and its gone. So next week Im having both of them re-balanced by a local performance shop my buddy owns and we should be golden, and again, Thankyou for the speedy helpful replies @Mebes and others

 

[m_ice]

Update. Pulled front driveshaft and did a "fast" run to the parts store and its gone. So next week Im having both of them re-balanced by a local performance shop my buddy owns and we should be golden, and again, Thankyou for the speedy helpful replies @Mebes and others

That's strange...

 

[Randall Ave]

Are you mabey stuck in four wheel, and don't know it? Are all the u joints free?

 

[Brettny]

Thats not odd or strange. These trucks dont disconnect the front driveshafts from the wheels in 2wd.