Drive Line Vibration?

stikine · 10-05-2010, 02:56 PM

Was looking for any advice regarding some vibration I'm getting at highway speed, quite noticeable around 65 mph which is my top speed I drive at. I first noticed it in July, but maybe it was always there since I purchased the van in late winter.

The vibration is a bit subtle, but I feel it in the seat of my pants, and when I let off the accelerator it stops. My BFG AT's are near the end of their lives, but other than some cupping on the inside of the front tires, and a few chunks missing from the outer knobs the tires are not too bad.

Any help appreciated.

Scott

Bones_GSXR · 10-05-2010, 03:16 PM

If it is a driveshaft vibration it is more like a hum and you can feel the whole body vibrate. Tierod, ball joint, and tire you usally feel through the steering wheel.
If the driveshaft is out of balance it is at all speeds but can get worse at you go faster.
If the pinion angle is off it usally comes on at one speed but after that it ismuch worse, but if you slow from that speed it gos away. This is do to the ujoints turning at different speeds, when you hit that magic number you get a vibration as they start to fight. mine does this at 63 or higher. I am milling a 7 deg shim to fix mine.

Lots of info on driveshaft building on the web.

stikine · 10-05-2010, 03:56 PM

Thanks - something I will have to add to my list to check into.

jage · 10-05-2010, 05:32 PM

Discount Tire will balance and rotate your tires for something under $50, or rotate them for free. Even if you're not a warranty holder with Discount Tire, it's a good way to check that it's not your tires... I've had BFGs that wouldn't take a balance after many years and had to replace them. I've also got slight cupping on my one of my Nittos from not rotating them for 17K miles. Shhh! Don't tell anyone I raved to about the Nittos! Actually I can't really feel now that they're on the back.

stikine · 10-08-2010, 09:18 AM

Well the vibration I was getting turned out to be a bad rear U-joint. Only 29,000 miles on the van and it was in bad shape - had it in at the Ford garage as there are some engine issues they are looking into also.

Wonder if the lack of any grease zerks back there is the reason for such a short life?

carringb · 10-08-2010, 01:18 PM

Hmmmm. My first set of U-joints lasted 260,000 miles. They were "sealed" joints - aka non-greasable. But.... Oregon doesn't allow road salt, so I think our vehicles are saved from some corrosion issues others face.

surfnfire · 01-12-2016, 10:30 AM

Hey there, I just came across your post, although really old, I just started having the same problem (33K). Were you getting a thud as well when re-accelerating? I have the vibration at freeway speed, and though rear ujoint as well. Did that fix the problem for good?

Quote:

Originally Posted by stikine

Well the vibration I was getting turned out to be a bad rear U-joint. Only 29,000 miles on the van and it was in bad shape - had it in at the Ford garage as there are some engine issues they are looking into also.

Wonder if the lack of any grease zerks back there is the reason for such a short life?

rexracer530 · 01-12-2016, 03:39 PM

I had this same problem this past summer. It turned out to be the rear u-joint. It was on it's last legs, it failed and took a chunk out of the yoke just as I got it to the mechanic to repair. That probably could've been bad at highway speeds if the driveshaft came off.

**daveb** · 01-12-2016, 06:29 PM

I had the same issue a few years back with the rear U joint. Limped from Ely to central ca. I had the drive line balanced and gone over when they installed a new U joint after I got home. No more vibration.

WhitH · 01-13-2016, 11:00 PM

I suspect I'm having a similar issue. Been thinking I had a weight get knocked off a rear tire and just need a balance but I had them done not too long ago so now I'm not so sure. Comes on right at 63 mph as well and is in the rear. Any visual clues I should look for beyond a chunk missing from the U joint?