...vibration

[85runneroc]

Well i own an 85 4runner. Its had a pretty bad vibration since the day i bought it. I have been slowly working my way up the drive train trying to make it stop. So far i have rebuilt the rear diff and replaced the u-joints. The more i fix the worse it gets.

the symptoms...
faster than 55 non stop gets worse the faster i go. Doesn't matter if i'm on or off the gas, in neutral or have the clutch pushed in. just a nasty vibration.

Any ideas on what it could be?

Oh found some slop in the transfer case not sure if this is normal or not. Not lateral slop, rotational. And the output seal is blown, spewing oil.

 

[KidVermicious]

Try rotating the tires to see if it changes? Check tire wear and your axle seals for maybe a bent axle? Disconnect the rear driveline and drive around in front wheel drive for a bit to see if that makes it go away?

Just some ideas.

 

[Hyde802]

Is it lifted? Bent drivelines? I also agree with kidv about the tires being out of balance.

 

[fourwd1]

Tires would be the first place to start.
Try rotating the front to the rear.

 

[85runneroc]

would a blown output seal cause a vibration?

 

[KidVermicious]

would a blown output seal cause a vibration?

The reverse I should think, but I'm no expert...

 

[85runneroc]

sorry man not seeing eye to eye... is that a yes?

 

[KidVermicious]

I don't think it's the blown seal causing your vibe, but it could be that what blew the seal is causing the vibe, is what I'm saying.

Or they could be unrelated.

 

[mpleitez]

I did a SAS on a 93 and for me I had death wobble don't know if that's the same but for me it was bad alignment. Once it was aligned it all went away, mine was cruising and all of a sudden wobble or when braking.

 

[4runnertank]

I just had this exact same problem at that EXACT speed. Ended up being by rear pinion bearing. Try jacking up the rear end, throwing the truck in neutral, then twisting the driveshaft/turning the tires. If its jerky or rough by the diff, suspect one of the bearings being out. mine was so bad it was banging around to the point i could hear it goin out of the driveway. Bearings only need a few grains of sand to screw it up. May also be the rear output bearing on the back af the T-Case. Just an idea.

Heres a pic of what i twisted and felt all crudded up in the output pinion bearing

 

[Pyroboy]

I had something similar and it turned out to be an poorly machined drive shaft slip. It was off-centre. Good to check your driveshaft balance and trueness.

I chased everything you have. Even replaced the rear wheel bearings and balanced the brake drums. Took me months to figure it out.

 

[85runneroc]

thinking its the output bearing. Just had 4.88s installed about two weeks ago. with that came all new bearings in there. same day i installed an all pro transfer case mounted parking brake. i think a may have effed up the output bearing while removing the stake nut on the output flange :/ that is the day that the epic vibration started multiplying instead of just existing. i'm taking it to a local mechanic tomorrow that does awesome work to hopefully have it diagnosed so i'm not chasing it anymore.