vibration troubleshooting

[gahammerle]

Finally made it here from the other place.

I need help troubleshooting a vibration while driving.

I feel the vibration in the seat, not through the steering wheel. It gets worse as vehicle speed increases - really bad above 70mph. Sometimes the vibration is not as bad as at other times, but there is always a vibration. I have about 133k miles on it.

This is the maintenance I've done on suspension parts:

2k ago: both front lower ball joints and tie rod ends, and left front end link
4k ago: tires
5k ago: right front hub
10k ago: right front upper ball joint
47k ago: left front upper ball joint, left front end link, left front hub, all 4 rotors

When applying brakes, I do not feel a pulsing like I would from warped rotors. The steering wheel does not shake. I do not know if the transfer case or diff oil has been changed prior to when I bought it at 84k. I have not changed it or checked level. I have rotated tires front to back and the vibration did not change.

When i was replacing the lower ball joints, I noticed grease thrown like it was from a torn CV joint on both sides in the front, but I did a quick look at the boots and did not see any tears. I would not rule out a tear since it was a quick look and I was on my back in the driveway.

Would bad CV joints click like a front-wheel drive car if the 4WD is not engaged? Should I engage 4WD and see if it clicks? Would bad CV joints cause vibrations? Is it possible to pull the front drive axles and drive without them in place?

Thanks for any guidance. I don't want to just replace parts without a high confidence that the part is what is causing the vibration.

 

[jrSS]

I know bad motor mounts can cause a vibration.

 

[gahammerle]

Is there a way to tell if the motor mounts are bad?

 

[CaptainXL]

If the vibration gets worse as speed increases then it is a rotational mass out of balance. Either the tires, front or rear driveshafts or from cv half shafts.

I would concentrate your efforts into inspecting and possibly repairing the half shafts first. There shouldn't be any grease flung from them. I would also double check your wheel balance.

 

[gahammerle]

Is it possible to pull the driveaxles and drive without them?

 

[The_Roadie]

The passenger side is no problem except for keeping the hole clean to preserve the bearings. The drive's side goes straight into the differential and the oil will drool out if you don't seal it with a Gatorade lid. Since new aftermarket ones only cost $50-60, and removing the existing ones is 80% of the work of replacing them, depending on your budget you might just swap them as a preventive measure. Or make sure all other possibilities are gone through first.

Offroaders all know this trick that a buddy of mine invented when I had to remove a CV shaft on the trail.

 

[gahammerle]

I replaced the drive axles yesterday and on the short test drive, that seems to have eliminated the vibration.

After examining the old axles, the boots were not torn. It seems the large clamps on the inboard boots had loosened and the grease was escaping out the end of the boots.

Unfortunately, one of the wires for the ABS sensor broke right at the sensor when I was putting it back together, so I get to order a new sensor and install that next week.