GMC Truck Driveshaft ?

I’m trying to figure out a vibration in my truck. Just replaced the 2 rear u-joints, and also the idler and pitman arms, had front end aligned. Also have 4 brand new tires. Vibration is not as bad now, but is still noticable when accelerating from a stop and once you get above 60mph. Do you think the driveshaft would need to be re-balanced? Any other ideas/suggestions?

The truck is a 2003 GMC 1500HD. I do have the torsion bars turned all the way out and 2″ blocks in the rear – not thinking that should make a difference though? Getting a little frustrating…..

4×4? Check the front U-joints. I had a vibration in my ’03 and it turned out to be the front drive shaft U-joints. I could feel the slight vibration in the accelerator.

Yep. checked them and they were fine. guess if nothing else i could just replace them as well, rather inexpensive.

Transfer case is possible. Hopefully not that.

Drive shaft angle could be too steep causing the drive shaft to bind under torque.

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Drive shaft angle could be too steep causing the drive shaft to bind under torque.

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Suppose that could have happened when I turned out the torsion bars? Might have to lower them a little?

I’ve only seen this when a lift kit is installed in a gmc. Gmc has the full time 4wd t-case. We had one where we built a custom drive shaft and changed the pinion angle. Still vibrated at hwy speed. Rebuild the t-case and it had wiped out the rear bushing and bearing in the tcase. After rebuild it still did the same thing. My advise is but it back to stock ride hight.

Pretty sure i don’t have a fulltime 4WD transfer case. The front shaft only spins when engaged in 4WD. After looking at the suspension lift, the angle of the driveshaft isn’t much different than it was at stock height.

did you change tires recently?
Loosing a wheel weight?

Also, sometimes……..when people put on aftermarket tires, or even doing breaks, when the rotors are pulled the little “clips” that slide over the wheel studs can cause this. Remove all “clips” off of the wheel studs, holding the rotors on.

Biggest question is if it vibrates under load and coasting or just under load (foot pedal applied).

x2 i’d say wheel weights. i have a 04 gmc 2500hd and cranked the torsion bars. not a good idea chewed up the front end too much replaced parts 3x in 7yrs going on 4th soon. went with leveling kit better ride too. as for the vibrating my does it when it go over 60 when i put new tires on. it didnt do it before the new tires so think its just a bad balancing job or lost weights. the torsion bar being cranked wont change drive shaft angle just the cv joints and eat up ball joints.

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Pretty sure i don’t have a fulltime 4WD transfer case. The front shaft only spins when engaged in 4WD. After looking at the suspension lift, the angle of the driveshaft isn’t much different than it was at stock height.

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Do you have a switch for the 4wd on the dash? If so than what i said eariler wont likely apply. I also agree that the wheel balance get checked. The only reason I posted what i did was if after you rule out anything else being the cause of the vibration that this is something I have ran into in the past.

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did you change tires recently?
Loosing a wheel weight?

Biggest question is if it vibrates under load and coasting or just under load (foot pedal applied).

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Put new tires on a couple weeks ago, but just had them re-checked today so it’s not the tires.

It only vibrates when accelerating from a stop and then when i get to about 60mph.

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Do you have a switch for the 4wd on the dash?

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I do

have you had your wheel bearings checked?

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x2 i’d say wheel weights. i have a 04 gmc 2500hd and cranked the torsion bars. not a good idea chewed up the front end too much replaced parts 3x in 7yrs going on 4th soon. went with leveling kit better ride too. as for the vibrating my does it when it go over 60 when i put new tires on. it didnt do it before the new tires so think its just a bad balancing job or lost weights. the torsion bar being cranked wont change drive shaft angle just the cv joints and eat up ball joints.

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I’m beginning to think i should have just went with the leveling kit as well. Damn young guys at the service station in town talked me into the lift!!

Why the he77 can’t GM lift theses trucks up a little bit to start with?

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have you had your wheel bearings checked?

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yep, checked those as well.

it would be nice. ive looked into a solid axle conversion with a dana60 to do away with the IFS. and it lifts the truck 5″ up front.

When did this start? Right after the lift or right after new tires? Vibrations can be a pain to figure out and it could be any number of things.

The 60 mph vibration could be a driveshaft, but I don’t think the vibration at acceleration would be. It’s easy enough to pull the driveshaft and get it check. I did this a few months ago on my 2001 Suburban that I just bought as I was getting a bad vibration at 65-75mph. Turns out the driveshaft was way out of balance. I had AA driveline in Anoka check it out and the shaft was strait and the original weights were still on it, but somehow it was way out of wack. After adding some pretty big weights to both ends of the shaft it is balanced and 80-90% of my vibrations are gone.

You could also pull the front and go for a drive to rule that shaft out. Otherwise make sure wheel bearing and u-joints are in good shape, and make sure the tires have been balanced. I would pull the shaft out to check this as a small amount of binding in the u-joints could cause some vibration, even if they are not loose.

Not sure what T-case is in that truck but i know my front drive shaft spins when not in 4×4 and I can’t turn it by hand when under the truck.

With vibration from acceleration your problem is obviously load dependant and not RPM. I still guess transfer case or maybe even tranny.

Probably way off here, but a bad plug or weak plug wire will feel like a vibration, esp under load.

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Probably way off here, but a bad plug or weak plug wire will feel like a vibration, esp under load.

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Good call. That may be my new favorite.

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did you change tires recently?
Loosing a wheel weight?

Biggest question is if it vibrates under load and coasting or just under load (foot pedal applied).

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Put new tires on a couple weeks ago, but just had them re-checked today so it’s not the tires.

It only vibrates when accelerating from a stop and then when i get to about 60mph.

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Did it vibrate PRIOR to the new tires?
Check for those clips on your rotor hubs….They are notorious for causing this!

Thanks for the replies guys, greatly appreciated. Never thought of the plugs – i do have 85k on the truck and haven’t replaced, so i’ll check them as well. Didn’t realize that would cause vibration.

It did vibrate b4 the new tires, so i’ve basically ruled out tires since the vibration is only when under load.

Thinking about all this, I am beginning to think it MIGHT be related to the suspension lift. I can’t recall this issue prior to that, or at least not as noticable…. sure is frustrating!

I know I had to drop the transfer case in my Jeep Wrangler when I lifted it 2″ due to driveline vibrations…but that is obviously a much shorter wheel base.

FWIW, I chased the same issue on a GMC for over a year. Turned out to be ring and pinion slop in the rear diff. It was an absolute nightmare figuring out, I ended up doing many of the same things that have already come up here. Any front seal leaks at all? Just a thought…

Thanks Czech…. I’ll keep that in mind.

Would a transfer case going bad make a whistling sound?

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FWIW, I chased the same issue on a GMC for over a year. Turned out to be ring and pinion slop in the rear diff. It was an absolute nightmare figuring out, I ended up doing many of the same things that have already come up here. Any front seal leaks at all? Just a thought…

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So did the rear pinion yoke have play in it then, or do you know what exactly what the slop was allowing to vibrate? Was the pinion seal leaking?

It’s been few years (it was a ’97) so I may not have the details exact, but yes, the front seal by the yoke was leaking a bit. We ended up opening up the diff and there was play on the side gears outside of tolerance, I ended up replacing those and that fixed the problem. The ring was ok if I recall correctly, just the side gears. Like I said, this was after numerous U’s and wheel balances, etc, over a year of trouble shooting.

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FWIW, I chased the same issue on a GMC for over a year. Turned out to be ring and pinion slop in the rear diff. It was an absolute nightmare figuring out, I ended up doing many of the same things that have already come up here. Any front seal leaks at all? Just a thought…

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So did the rear pinion yoke have play in it then, or do you know what exactly what the slop was allowing to vibrate? Was the pinion seal leaking?

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