Highway Speed Vibration

[Mattbuyshouses]

Hey all.

I've had a problem for as long as I can remember (no funny jokes now). I've searched all over the forum but haven't seen anything that exactly describes what I'm experiencing.

At 65mph and greater there is a vibration that can be felt and that closely resembles running over those grooves cut into the shoulder of the highway. A similar sound is made as well. The noise and vibration are considerably more intense when selecting 4WAuto on the 4x4 switch. Also along the same lines while cruising at highway speed and then stepping on the throttle to pass an initial mimic of that sound can be heard for about a second as the trans shifs out of OD for a passing gear. After only a second it's gone during this event.

The first situation I mentioned has been around for quite awhile. I had the ujoints for the front and rear shafts replaced about 4 years ago, recently as posted in another thread I've replaced the half shafts, ball joints, brakes, and about 3 years ago the transmission was rebuilt.

I've seen other people experience something similar but never exactly the same.

If anyone could help me diagnose this darn vibration I would greatly appreciate it.

I'm having the rear shocks done tomorrow and we are checking the fluids in the front and rear diffs as well as inspecting (possibly replacing) the ujoints as well.

Matt

 

['97 V8]

ive heard people getting vibrations becuase the rear out put was loose....like the driveshaft connectong to the t-case in the rear moves. I forgot what its caled though..

 

[Mattbuyshouses]

I'll check out the ujoints and driveshafts for play tomorrow when it's on the lift.

Is there a transfer case in the rear that I'm missing? I thought it was just a rear differential. Oh well, I'm not a mechanic by any stretch but I do love learning this stuff. I'll work with the mechanic tomorrow and see what we can find.

 

['97 V8]

well yeah. after the tranny you have a transfer case. The driveshaft leaving the transfer case going to the rear axle is what im talking about. Right were the driveshaft is connected to the rear of the transfer case, grab it. move it up down, side side whatever, just check to see if there is play in it.

 

[hunterdan]

I had a severe vibration in the rear that had some noise to it. Took it to a tire shop and had the tires rotated and rebalanced. Went for a drive on the PA Turnpike, decided to make a pit stop and figured Id wiggle the driveshaft. Turns out the front yoke on the driveshaft that mounts to the transfer case was loose. All 4 bolts were backed out atleast 1/4" if not more. Make sure everything is tight. I tightened them back up and the vibration was gone. Made for a ride that was smooth as glass. Tire shop told me the vibration could be my u-joints, even though I had just replaced them.

Dan

 

[Mattbuyshouses]

Was the vibration you had at certain times or did it happen just any time the vehicle was moving? Mine is only noticable at 65+ and as the speed gets higher it gets exponentially worse.

 

[Mattbuyshouses]

Finally resolved!
Ok, so today I took the XPloder into the driveshaft shop for a couple reasons:
1.) The front shaft u-joints (and CV joint) couldn't be replaced at my local shop.
2.) I wanted to have both shafts checked for balance

Last week I had a local mechanic replace the rear shaft u-joints but still had the bad vibration at highway speeds. I hadn't yet had the wheels balanced but still wanted to get the front shaft u-joints replaced since all the u-joints were the same age and the back ones weren't in the best of shape.

The rear shaft got balanced with only 10grams of weight added.

The front shaft has that CV joint (where two u-joints meet up) and the ball and socket in between them was worn out.

I tried taking a picture of it with my phone but it's too blurry and wasn't much help to anyone I don't think.

The front shaft needed about 20-25 grams of weight added to it and all 3 u-joints replaced. The two rear u-joints (making the CV joint) are greaseless joints now since they are so hard to get to once the T-Case shield is back on. I used a greasable joint on the front since it's easier to get to and both rear shaft joints are greasable as well.

Well anyway, I got it out on the highway at about 75MPH and NO VIBRATION any more.... unbelievable what around 20-30 grams of weight on those shafts will do! So the shafts were BOTH out of balance, even if only by a little bit.

I'm taking it out again in a few minutes to put a good test drive on it, switch it in and out of 4WAuto and check for any vibration or noise and just to revel in my once again smooth ride.

The bill for today if anyone's interested was:
u-joint [2 pcs] - (list=32.14) discount cost = $24.11ea
center yoke - (list=122.36) discount cost = $85.65
dust shield - (list=4.67) discount cost = $3.50
R&R shafts [2 pcs] - $35.00ea
balance shaft (rear) - $60.00
balance shaft (front) - $75.00
u-joint [1 pc] (list=20.90) - discount cost $10.49

With tax it came to $363.58

I would have saved about $70 more if I had taken the shafts off and installed them myself but I don't have a second vehicle so no way to get down there. Plus, it only took about an hour and a half for them to do everything so it was done while I stood there and bugged them about "what's this? what's that?"

If you see a spot weld point on either of the shafts and you've got a vibration, it might make sense to have it taken in and balanced again. It did with mine.

Hope that helps someone.

Matt

 

[stilbo]

Matt...

If you see this, has your problem stayed away?

I am a Level II Vibration analyst but I quit that job two years ago and don't have any diagnostic equipment anymore. Just one reason that this vibration is driving me nutz! Anyway, I'd be pretty peeved that new driveshafts are being sold that need more than an ounce (!) of balance weight! At the relatively low rpm that these shafts turn I could understand needing a few grams but a new shaft that is out of balance that bad should be tossed through the parts store window! (just kidding...)

I had a local shop install a new shaft on my '96 Limited and they replaced the rear shaft U-Joints and the vibration has been there before and since... I will be going to a driveshaft machine shop (if I can find one around here) soon. You are about 75 miles from me but just in case... what is the name of the shop that balanced your shafts? Thanks, Ron

 

[Mattbuyshouses]

Ron,

I had Rockford Driveshaft fix the balancing on mine and it's been running great since.

 

[stilbo]

Matt,

Thanks for the info on Rockford...

The local shop pulled my front driveshaft and I've been driving 85 miles a day and the X is as smooth as a new Lexus. The shope apparently has a machine shop that does shaft balancing for them. This shop sent the saht back today and sadi that it is too far out of balance to try to balance. The small bearing in the end was shot and the yoke is seized on the shaft splines. The shopa manager said that the parts guys told the manager that there was only ONE size shaft but I have checked three suppliers and they come up with TWO lengths. I'm getting the feeling that the shop may have put a shaft in that was too long and it jammed the splines at the end of their travel and seized them and wore out the small pilot bearing. I'm going to run the past the shop Monday. My biggest problem now is that the shop tossed the original shaft so I don't know what it's length is...