Vibration at 60MPH (100KPH)

[J33P]

1044596

I tried doing a search but I can only get 3/46 viewable for some reason...



Anyhow, When My Jeep hits 100KPH, it starts to vibrate/shake very bad. It doesnt matter if I'm in 3rd , 4th or 5th gear it starts shaking always at the same speed.

I thought it was something to do with wheel alignment or wheel balance or something in the front end, but I've had two mechanic shops say that stuff is fine (not sure what they actually checked) and they say that it's something in the drive line. They suspect it could be U-Joints or that there is play in the drive shaft (which apparantly there is a little).

But I thought if it was the drive shaft that the vibration would be consistent at RPM level, not at speed? Isnt the drive shaft moving faster/slower when going between 3rd, 4th, and 5th?

[addsig]

 

[BobJ]

1044597

no, the drive shaft speed is consitant with wheel speed.[addsig]

 

[RayOvac]

1044604

I agree with Bob....the drive shaft is ALWAYS turning the same speed as your wheels...no matter what gear you are in. The gear your in only determines your engine rpm at any given speed. I had a similar prob with vibration when I lifted my jeep...it always occured between 30-40MPH no matter what gear I was in. Turns out that I made my driveshaft angle too steep. I lowered the transfer case and that was that...no more vibes. As for you I would definitely check out those U joints. Also another thing is that your driveshaft may be out of balance...I have heard of that happening b4. Sometimes a driveshaft gets a good dent or one of the little weights that balances it out falls off. I would inspect them carefully. You probably better get it taken care of soon because shaft vibes can tear up your pinons, x-fer case, U joints, and other stuff that can be expensive to replace.[addsig]

 

[MudderChuck]

1044607

Most times a 60 MPH vibration is wheel or tire balance. Try rotating your tires, front to rear and see if this doesn´t at least change the vibration. If a prop (front axle) shaft U-joint is bad this can also cause a vibration, but will also usually make a poping sound when going around corners. Bad front U-joints can be quickly inspected by looking closely with a flashlight, you will often see rust colored dust around the rubber ring (seal) around the U-joint bearings. Sure sign the U-joint bearnings are bad or failing. Close inspection of the play (should be 0) between the U-joint and bearing caps is also advisable on a regular basis.

[addsig]