Unknown and inconsistent vibration

[caulk04]

So I have this ongoing vibration that I'm unable to find on my own, HALP! Sometimes it starts around 55, sometimes higher, sometimes nothing all the way to 80. I've not been able to pin down a point at which it starts or any certain bump/turn that starts it either.

The vibe is general, you feel it in the seat, console etc. It does not shake the wheel. I'm 100% sure it's not the tires, it existed before and after getting new tires and also after I added balance beads to all 4 tires. Shifting to lower gears does nothing. Accel, coast, or decel does not affect it. I've shifted into low range and ran through the gears (maybe 40mph) and did not feel any vibes so it seems not to be transmission. Front driveshaft has been removed with no effect. Rear driveshaft ujoints are all smooth with no slack. Sometimes it's pretty light, others it's bad enough that I can just watch in my mirror to see the bed shake slightly in relation to the cab.

I've driven enough junk vehicles to know what various terrible suspension components feel/sound like, that is not the case here. I replaced the lower links on the rear axle as two of those bushing were slightly suspect; no effect.

The truck is a slightly odd bird being a 149" WB 1500. Hoping someone has fought this before and has a silver bullet for it.

 

[crackerjack1957]

Sounds like you have pretty much covered it all.........if vibration in the rear only thing I can think of is driveshaft not balanced or axle shaft in the rear end.
Don't really know the history on vehicle so can't say for sure.

 

[Daw14]

Carrier bearings good?

 

[Wild one]

Is it a 2 piece driveshaft ,wonder if it could be a bad steady/center bearing

 

[tidefan1967]

Pinion angle slightly off maybe?

 

[caulk04]

One piece drive shaft.

Nothing has happened to the truck for the pinion angle to be wrong, though I suppose I could check it sometime.

 

[crackerjack1957]

Mileage when it started or when vibration started?

 

[mdc1990zr1]

So I have this ongoing vibration that I'm unable to find on my own, HALP! Sometimes it starts around 55, sometimes higher, sometimes nothing all the way to 80. I've not been able to pin down a point at which it starts or any certain bump/turn that starts it either.

The vibe is general, you feel it in the seat, console etc. It does not shake the wheel. I'm 100% sure it's not the tires, it existed before and after getting new tires and also after I added balance beads to all 4 tires. Shifting to lower gears does nothing. Accel, coast, or decel does not affect it. I've shifted into low range and ran through the gears (maybe 40mph) and did not feel any vibes so it seems not to be transmission. Front driveshaft has been removed with no effect. Rear driveshaft ujoints are all smooth with no slack. Sometimes it's pretty light, others it's bad enough that I can just watch in my mirror to see the bed shake slightly in relation to the cab.

I've driven enough junk vehicles to know what various terrible suspension components feel/sound like, that is not the case here. I replaced the lower links on the rear axle as two of those bushing were slightly suspect; no effect.

The truck is a slightly odd bird being a 149" WB 1500. Hoping someone has fought this before and has a silver bullet for it.

I always try to get American made whenever possible. When I couldn't get American made Goodyear or Firestone tires for my 3500 truck, the supposed tire guru at The Tire Rack steered me to this great Kuhmo tire. Short on options, I reluctantly ordered a set of four. These tires didn't last two years before the two rear tires exploded a day apart from each other. In the interim, I also chased a mysterious vibration. Tires were remounted and rebalanced by everyone I took them too. A few alignments were done, rotations, even a rear driveshaft was done. Nothing solved the vibration. One summer day while passing the Philadelphia Airport, one rear tire separated and I put on a spare. The very next day, the other rear tire exploded. On with the other spare. I have extra wheels and tires and some dedicated winter tires for the 2WD trucks. Low and behold, no more vibration. I saved the old tires for warranty purposes. The Kuhmos must have had internal tread separation that could not be detected or balanced out. I called The Tire Rack and they could care less. Not satisfied, I left a scathing review that they never posted. Buyer beware when dealing with The Tire Rack.

 

[670hoth]

It's wear on the splines of the front CV shafts.

 

[caulk04]

It's been doing it for a long time, since maybe 40k. There's just shy of 80 on it now. I think it's getting worse.

Front CV's...hmm. I hadn't really considered that. Once upon a time I had an 02 Dakota that wore the intermediate shafts and CV's to the point that they just spun. Maybe I'll take a couple hours one day and pull the shafts out to see if there's any change.

Can anyone confirm that the CV stubs are not needed in the wheel bearings and you can drive without them?

 

[Wild one]

It's been doing it for a long time, since maybe 40k. There's just shy of 80 on it now. I think it's getting worse.

Front CV's...hmm. I hadn't really considered that. Once upon a time I had an 02 Dakota that wore the intermediate shafts and CV's to the point that they just spun. Maybe I'll take a couple hours one day and pull the shafts out to see if there's any change.

Can anyone confirm that the CV stubs are not needed in the wheel bearings and you can drive without them?

Haven't had any 4X4 parts in mine pretty well since it was new Jesse.Front hubs are the same part number whether 2X4 or 4X4,so you don't have to worry about the front tires falling off.

 

[caulk04]

Excellent, I thought I had read that before but wasn't willing to bet on a thought.

 

[Sherman Bird]

It's wear on the splines of the front CV shafts.

Man! I'm impressed! Please! Share with me where you got YOUR 8 ball!

 

[Jeepwalker]

Bent wheel? Bent Axle? Bent Hub? Failed shock absorber?

Were your tires/wheels balanced (checked) on a Hunter Road Force Balancer? Most balancers will attempt to balance a bent wheel, and you'll never know if it's bent. Tire guys in a hurry (which are all of them!) don't really look for bent wheels. I've bought a lot of tires in my days for the myriad of vehicles I have. And I don't recall ever seeing a tire tech check for a bent wheel, unless it is seriously out of whack. I always look at the wheel as it's spinning. Also, I bought 5 used but nice aluminum Corvette wheels and, yeah, every one of them is slightly off/warped when checked with a dial indicator. Some enough to cause shake. They can stack weights to acomodate for the warpage, but it can still shake on the road. The Hunter Road Force Balancer will catch & alert for a bent wheel right away. Just wondering if that was done?

Could also be a bent axle or a (no good) hub/bearing assembly (maybe since new??). I bought a brand new front wheel bearing/hub at OReilly's 1.5yrs ago which was .005" deflection at the hub face OUT OF THE BOX. This was a brand new bearing/hub. It looked good. Good thing I put a dial indicator on new parts when I get them. That amount of deflection at the hub face would translate into a lot of wheel movement at the tire, and definitely produce a vibration. I took it back to the store. Who knows ...they probably re-stocked it and sold it to the next guy!

So, it wouldn't hurt to check things like that, incl a failed shock absorber which can allow wheels to bounce going down the road (maybe that's what knocked out the Kumho tire/s?).

_

 

[Sherman Bird]

So I have this ongoing vibration that I'm unable to find on my own, HALP! Sometimes it starts around 55, sometimes higher, sometimes nothing all the way to 80. I've not been able to pin down a point at which it starts or any certain bump/turn that starts it either.

The vibe is general, you feel it in the seat, console etc. It does not shake the wheel. I'm 100% sure it's not the tires, it existed before and after getting new tires and also after I added balance beads to all 4 tires. Shifting to lower gears does nothing. Accel, coast, or decel does not affect it. I've shifted into low range and ran through the gears (maybe 40mph) and did not feel any vibes so it seems not to be transmission. Front driveshaft has been removed with no effect. Rear driveshaft ujoints are all smooth with no slack. Sometimes it's pretty light, others it's bad enough that I can just watch in my mirror to see the bed shake slightly in relation to the cab.

I've driven enough junk vehicles to know what various terrible suspension components feel/sound like, that is not the case here. I replaced the lower links on the rear axle as two of those bushing were slightly suspect; no effect.

The truck is a slightly odd bird being a 149" WB 1500. Hoping someone has fought this before and has a silver bullet for it

Bent wheel? Bent Axle? Bent Hub? Failed shock absorber?

Were your tires/wheels balanced (checked) on a Hunter Road Force Balancer? Most balancers will attempt to balance a bent wheel, and you'll never know if it's bent. Tire guys in a hurry (which are all of them!) don't really look for bent wheels. I've bought a lot of tires in my days for the myriad of vehicles I have. And I don't recall ever seeing a tire tech check for a bent wheel, unless it is seriously out of whack. I always look at the wheel as it's spinning. Also, I bought 5 used but nice aluminum Corvette wheels and, yeah, every one of them is slightly off/warped when checked with a dial indicator. Some enough to cause shake. They can stack weights to acomodate for the warpage, but it can still shake on the road. The Hunter Road Force Balancer will catch & alert for a bent wheel right away. Just wondering if that was done?

Could also be a bent axle or a (no good) hub/bearing assembly (maybe since new??). I bought a brand new front wheel bearing/hub at OReilly's 1.5yrs ago which was .005" deflection at the hub face OUT OF THE BOX. This was a brand new bearing/hub. It looked good. Good thing I put a dial indicator on new parts when I get them. That amount of deflection at the hub face would translate into a lot of wheel movement at the tire, and definitely produce a vibration. I took it back to the store. Who knows ...they probably re-stocked it and sold it to the next guy!

So, it wouldn't hurt to check things like that, incl a failed shock absorber which can allow wheels to bounce going down the road (maybe that's what knocked out the Kumho tire/s?).

_

We had a new GMC Suburban at a dealer I worked at back in 1993 that had this type of shake/ vibration. After our other well meaning technicians attempted "shotgun" repairs (The last one I worked on had a bad.... fill in the blank....), the service director and the shop foreman came out and gathered several of us mechanics and explained that he (we) needed to fix this truck because it had been at our shop for a week, and the customer had a coupon book and no new car!

I recommended that we fetch the NVH tool (noise. vibration, harshness) and collectively, as a team, figure it out.
We did so, and figured that the axle tube on one side was welded in crooked! This meant that an entire new differential assembly had to be installed. To expedite, we took one off a new Suburban in stock with a matching differential. and it was fixed! That took an act of congress from the Detroit ivory tower to cannibalize a new truck in stock.... they had to rubber stamp it and a lot of documentation was necessary.

 

[caulk04]

Welp, it's not the CV shafts. Pulled them, no change.

Put the rear axle on stands and ran the truck, the only thing that didn't feel buttery smooth was the output of the tcase. Didn't feel bad, but it was the only thing where I could feel anything. The only other thing I can think to do now is fine a shop that can check the rear shaft for balance or find a new one.

 

[Wild one]

Welp, it's not the CV shafts. Pulled them, no change.

Put the rear axle on stands and ran the truck, the only thing that didn't feel buttery smooth was the output of the tcase. Didn't feel bad, but it was the only thing where I could feel anything. The only other thing I can think to do now is fine a shop that can check the rear shaft for balance or find a new one.

Well it was worth a shot,at least you've ruled out anything to do with the front 4X4 parts.For sh!!ts and giggles have you checked the cab and box mounts,i can't see it being them,but it might be worth throwing a socket on them and making sure they're tight

 

[caulk04]

I haven't done that, but easy enough to check.

 

[Travelin Ram]

As I was working my way down the posts I was thinking you need to find a shop with a vibration analyzer. See @Sherman Bird ’s post.

They are a bit costly for a home mechanic or one time user. Sometimes it’s worth paying a pro. Finding one is the hardest part.

 

[Bigskyroadglide]

Have you checked to see if your parking brake shoes are performing as expected? And not hanging up, causing vibration. Whether you routinely use the parking brake or not.

Just a thought.