1999 2500 QC 4x4 5spd. I have been trying to find and fix a vibration which can be felt above 50mph and is a resonant vibration, meaning it will cycle in and out every second or two. It may be throughout the whole mph band, but mostly felt in the higher mph. Here is what has been done so far:

New Michelin LTX/MS tires 265/75/16
Replaced rims and road force balanced tires
New track bar
New outer tie rod ends
New drag link
New steering stabilizer
New front/rear shocks
New carrier bearing
3 new rear driveshaft u-joints and rebalanced driveshaft.

Now some of this was preventative maintenace and needed, but the problem is still there and has been there for a year at least. I just really noticed it recently since I am now driving on the highway to work everyday and it's makeing me mad.

One note, if I press in clutch and RPMS go from 2400 to 700, the vibration is still there as the truck decreases in speed.

I did havd drivers side upper/lower ball joints and I think hub bearing replaced about 4 years ago, and last night I noticed a MISSING bolt(1 of 4) in the hub. Couldn't be that simple could it?

Anyone know the size of that bolt?

Any help is appreciated.

Thanks

 

Do you feel it in the steering wheel or the seat of your pants? Could be a brake drum out of balance. Ive seen that too many times in my shop.

 

i see you replaced the rear u-joint 3 times. what about the others? and is the rear u-joint seated in the yoke properly. also is the truck lifted? if so the pinion angle may be off. one more thing is the drive shaft in faise.

 

Leading Q. read me your oil P. hot @ idle and then @ 1500 rpm.

 

It's more felt in seat of pants, but you can see the front hood rattle side to side.

No lift, and I recently replaced all 3 u-joints at 105K miles, not three times.

I have jacked up rear of truck and run truck to 75mph and NO vibration, so that should rule out drums.

I don't have an oil pressure guage.

 

look @ the harmonic Bal. and see if the outer ring is @ a diff depth then the inner...they should be about the same all the way accross or all the way around..
You should have a oil P. guage or did they delete that in your yr ?

 

If the vib is still there when you press in the clutch then it rules out the engine and its components. When you changed the U joints did you check to see if the drive shafts have been twisted (out of sync)? Have you checked to see if you have a rim that's not running true? A rim or hub not quite true would only give a vib when the tire is in contact with the road and would show less in the rain. Try jacking up the back wheels and place something in close proximity to the rim ( a mag base would work well) then slowly rotate the wheel. It could be someone hit a curb hard with a back wheel and bent the hub or rim. I see you replaced your rims but one could still be out because of the hub

 

I don't suspect the harmonic balancer as it looks good and the clutch pressed in I would think eliminates that as the culprit.

I'll check oil pressure today at idle and 1500rpm.

I don't think driveshaft was put in out of synch as the exact same symptoms were there before I took it in for a rebalance and new u-joints.

I have been the only owner of the truck and have never hit something so hard that I would even consider a bent hub. Also, I have rotated all tires in every possible configuration and the vibration does not move, so I would think that rules out a bad rim.

I did tie the front driveshaft last night to prevent it from moving and problem is still there. Someone suggested from another forum that the front driveshaft through fluid motion in the differential/axles causes it to spin eventually.

Anyways, I am still looking for suggestions as it is now a vendetta.

 

Look real close at the carrier bearing...On mine, the rubber had shrunk up and I was getting some wierd vibration like you mention on the highway.

 

I already replaced the carrier bearing about 2 months ago.

 

Pretty soon I am going to ask you to pull the oil pan...Or maybe just drain your oil and stick you finger up in there and see if you find a green 1 inch long tube s

 

Thumper,

I checked my oil pressure as accurate as I could and idle is about 30psi and 1500rpm about 40.

What about the tube? At this point, I'll try anything.

 

Thumper seems stuck on engine issue and you say problem is still there with engine at idle. To me that rules out engine issue........
A vib that cycles in and out at 50 MPH. A vib that shakes hood and seat of pants is a low frequency vib. So that rules out drive line. A drive line issue will beat your ears out at 50 MPH. That pretty well locks in a 8-12 hz vibration from tires. Two tires with issues will cause a phasing in and out of vib. My suggest is borrow a set of stock tires and wheels and try them. The road force balance will not correct some tires issues that cause vibs. JMHO

 

I thought my original rims were bent possibly causing the issue, so I got a used set with 50K miles on them from a 2001 and the problem is still there, so I would hope the chances of getting rims with the same issue is low.

I took a drive today and really spent some time feeling the truck out and I do notice a vibration or something not smooth as low as 20-30mph. I think it just gets much more pronounced at higher speeds.

I am thinking really hard that my front hub bearings may be going out. No sound, but that really is the last front end part I can think of.

 

I have a similar vibration in my truck but it happens at 70-75 mph. Its not noticable above or below that. It doesn't happen when the truck is up in the air. All steering parts, ujoints, and bearing have been replaced in the past year. I need new tires, I dunno if that could be the problem. I never thought about checking the harmonic balancer.