Vibration; drive shaft, U joints, HELP!

[SoCalCruiser]

I've been having a vibration problem since I bought my '89 2 years ago. I'm going to sell it and need to find out where it's coming from.

The vibration starts at 55mph and gets worse the faster I go. Tried new tires, shocks, alignment.........on and on.

Any ideas? Thanks,

Craig

[miked]

start with u-joints and go from there. If no suspension mods then this is probably the deal. Remember to use high pressure grease and not chassis grease in the new u-joints

lots of threads on vibrations (I should know...) in here somewhere, do a search

[BK]

Is this the kind of shake that can loosen your teeth? I just took the waggy out last night after sitting in the driveway for the past month while I replaced brakes and fixed the rear window. Got on the highway at 55 just to run it a bit and it was shakin like crazy. First thing I would think is the tires are out of balance but I don't remember it being this way a month ago.

[SoCalCruiser]

naw, it just a vibration that feels like those massaging beds, but it builds.

My first thought was u-joints. Is it possible that the drums can do this? I had a break/muffler place fix my tailpipe and had them look at the rear breaks yesterday, and I swear the vibration changed (came on at lower speed) after they took off the drums. I think the drums might need replacing anyway.

Craig

[YAKFSHR]

bk, depending on what kind of tires you have, they get flat spots from sitting. usually bias ply tires but it should go away if thats the problem after they warm up or get some miles on them. had that problem with the tires on my 72 k5 blazer. wish i still had it.

[River Beast]

U-joints is my first guess... but they would be constant and grow with speed... if you say it starts at 55mph... that baffles me...

is it a constant vibe or comes and goes with accelator? Does it do it while coasting? Get up to 55-60 and go to nuetral.... see if it remains.... if so.... with all tension off the driveline... you may have something else going on...

[Kukur]

Mine has a vibration after I installed a rebuilt 360. But it is at high RPM (regardless the speed, does it in park).

Been told it is probably the dampner or flexplate. Since I re-used the old ones.

[CowKiller]

but the real kicker he said was that is has been doning it for 2 years. a u joint would of gone then. so it cant be that, i would keep checking stuff, out of ballance driveshaft?

[goofy289]

most of the time Brake drums have a balance weight atached,so if it fell of it could be a drum.it is strange that it dont start till 55. :confused:but a drums outer edge does sit close to the center of the axle so it might take alot more rpm to feel it.
Is the trans and motor mounts ok?Mine are all bad(this weekends project)and right now I have a slight vib due to the engine/trans sitting crooked.
G/L

[imported_Big Red]

Check to see if there are dents in your drive shafts. If so replace it.

[SoCalCruiser]

Drive shaft looks OK. It is a constant vibration, starts at 55 and gets progressively worse. Not teeth rattling, just a shake. Does it if I shift to neutral at 55+.

Over the last 2 years the speed when it starts is getting lower, used to be 65+, seemed to start earlier (55) after my breaks were checked the other day.

I thought drive shaft or u-joints until the break inspection.

Craig

Craig

[Dogs-in-the-back]

I feel your pain.
Ive swaped rims, bought new tires, had the shafts re balanced and all new joints. Still cant find it. This is just a hinch, but If yours draggs Great Googley MoogleyGreat Googley MoogleyGreat Googley MoogleyGreat Googley MoogleyGreat Googley Moogley in the rear, could it be throwing the pinion angle off a little. Best of luck.

[SoCalCruiser]

Not dragging, my '91 is, and I think it throws a lot of things off.

[irbob]

A couple other things would be a bad engine or trany mount and may be worn spider gear pins or pinion gear. You could also get vibration if a bushing is warn out, like a body bushing or leaf spring bushing. Oh yea and the infamis broken leaf spring or shock mount. Man there are a bunch of things it could be. Get on a creeper with a prybar and go from front to back checking that all is tight.

[SoCalCruiser]

Service manuals say that at 55mph+, audible vibrations that are not engine speed or torque specific is either drive shaft or u-joints.

Guess I'll start with u-joints first since this seems to be the most logical. Is it a big job?? I read the archives, but can't tell if it is.

Everything I do seems to take 2x as long as it should.

Craig

[DerekTJeep]

I've been having that same problem with highway driving in my '89. Thank for tips from you guys. It gives me idea of where to look for the problem.

Derek

[BK]

I just found out that my vibration on the highway is due to one tire where the steel belt has separated from the tire. Found that out when I had the 4 wheels balanced and they found it. Will be lookin for a used tire I guess.

[SoCalCruiser]

UPDATE:

Was the rear drive shaft u-joints. Put new ones in this afternoon, and no more vibration............at least not as bad.

Now it vibrates at 70+ and only on acceleration.......

Craig