Bad vibrations, need advise

[Kirk Risseler]

Ok, most of the front end components on my 4x4 Trac have been replaced at one time or another. I have a pretty bad vibration around 65 mph. Its not tires, rims, balancing, ball joints, tie rods. I just got new tires, an alignment and the whole front end checked out. The only thing they found (and I have been wondering about) is the passenger side cv joint. It is "seeping" a little and has a very little play to it. The tech said the front end is tight and this is the only thing he sees that has any play and its not much.

So, do you guys think this could be my high speed vibration???

Thanks for your help.

-Kirk

 

[Jerry Gerner 2]

Could be but usually at that speed it's a tire balance issue. I've had my tires balanced twice and one of them is out of round and just can't be balanced perfectly so at around 60-70 I get a nice noticable wobble/ vibration.

 

[Kirk Risseler]

For sure not a balance issue. I had my last set of wheels/tires balanced a few times and rotate them to see if the vibration moved to the back, never did. Now, I have brand new wheels and tires (i will have to post pics) and exact same vibration. Its driving me nuts.....

 

[jaydawg74]

This should fix it....... :supercool:

 

[Yardsale]

I have this same characteristic on my '01 Job 1 (211,000mi.) and attempted all the same remedies (wheel balance and rotation, alignment, check shocks and ball joints, etc.). It developed to a pretty good steering wheel wobble around 45-55 MPH.



Have the rack and pinion checked. You can check it yourself by lifting the front not by the tires and having someone shift each wheel left and right while touching the rack feeling for vibration indicating movement inside. If you feel this, have it checked-out, possibly by a couple of shops just to be sure (relpacement of the rack is an expensive repair and you want to be certain before having this done).



There a Chilton vibration chart in my library, but it doesn't address steering box or rack and pinion.

 

[Richard L]

Early 4X4 Sport Trac's had a vibration issue that Ford resolved by replacing the driveshaft with a new aluminum unit.



The only problem might be is that Ford claimed the driveshaft vibration only occurred above normal highway speeds of 70mph? If the vibration occurred at less than 70 mph, it was assumed the problem was a wheel/tire issue.



Anyway, those here that had the new driveshaft installed claimed it solved the problem...so I suspect that your driveshaft may be the problem even though it occurrs at a little under 70 mph> I suspect that the new driveshaft is not cheap so you might want to check some of the local junk yards and see if you can find a junked Sport Trac 4x4 with the aluminum driveshaft. (take a magnet to check).



...Rich

 

[Yardsale]

TSB 05-20-11 describes a band-aid for a vibration between 75-80 MPH on 2001-2005 vehicles with 4.10 differentials. The TSB states the condition MAY be due to a driveline imbalance. I am not certain, but believe that those vehicles came with steel drivelines.



Mine came with a steel driveline and 3.73 gears. I noticed the vibration when it was new at about 85 MPH. When I put 265/65-17 tires on it, I regeared the differentials to 4.10 and the speed at which I noticed the vibration reduced to about 73 MPH. With the gearing change, the rotational speed of the driveline, at a particular vehicle speed, increased.



I see that your vehicle is a prime candidate for this quagmire.



There was a lot of work done to fix the vibration, but it remains. I started with having the steel driveline rebuilt and balanced - twice. Both shops told me that the driveline was fine when I brought it in. Then, I went ahead and replace the steel driveline with a new aluminum driveline ($400+/-) and, while it did increase the speed at which I could feel the vibration, it was no better than before I increased the tire size and regeared the differentials.



Other attempts:

New transfer case rear cover, bearings, etc.; rebuilt the front driveline; aligned the transfer case output shaft with the differential input shaft; jack stand tested a bazillion combinations of two sets of wheels (stock and the Revos), two rear drivelines, one driveline front only and rear only, in 4WD and not. Checked the wheels for lateral and radial runout myself and sent them to the manufacturer for inspection



Long story short - replacing the steel driveline with an aluminum driveline reduces the rotational mass of the driveline AND all rotating parts to which it is attached. This does not FIX an out of balance condition any better than having the steel driveline balanced.



My speculation is that there is a driveline angle disparity in the horizontal plane (left t right) that can only be corrected by shifting the output shaft of the transfer case or input shaft of the differential, or by installing a double cardan, or some such, joint on one end of the driveline to reduce the angles. This is the only attempt I haven't yet tried.