Vibrations? ? ? ? ? ? ? ? ? ? ? ? ?

[bayrunner]

Hey Guys ____ I’m trying to isolate a slight vibration that I’m experiencing from 35-40mph in 2WD. It’s an 84Runner 5sp, with a 7in.sus.lift and a 2in body lift. This is not a rig I build up myself, instead a rig that was started by a friend and was unable to keep due to some unforeseen circumstances, anyway it seem that the rear driveline angle off of the differential might be a little excessive, I’m trying to bring my computer skills up to par and take some pictures and post them as of yet been unable to, but I’ll keep trying. It seems the differential was not rotated up at all, (from stock) and I’m wondering if re perching the rear springs(and rotating the diff up slightly) to get a better angle, might be one solution, or keeping the stock diff.angle and add a CV joint in driveline, anyways that’s my problem, and I was HOPING to go out on a limb and ask for some PICTURES(of the rear driveline angle going to t-case) of some of you guys rigs with similar lifts, I might be overextending myself by asking for pictures. ,but what the hell, I’ll give a try. _____ THANKS BAYRUNNER

[t96f]

A couple off the top of the head possible fixes could be, longer shckles to bring the rear of the spring down and pivoting the yoke upwards. Slant cat axle blocks to put the yoke up.
We are talking about the rear angle only? Or front ujoint issues to?

[bayrunner]

Hey Guys _____ I was thinking about my dilemma ( vibration),if the slight vibration was occurring between 35mph and 42mph and I’m in 3rd,if I shift out of 3rd and the vibration disappears , does that mean it could be in the trans.(third gear)even though the driveshaft(rear) angle is sharper than it should be. The driveshaft was trued, and the bearing from t-case is tight. It seems it only leaves the trans or the driveshaft angle.. –Anyway interested in your thoughts ____ THANKS BAYRUNNER

[kjmcdaniel]

Given the lift you described, I would think the most likely cause would be your drive line angles.

The best way to fix it is to add a cv, and point your pinion directly at the t/c, so that the lower U joint is straight.

If you maintain U joints, the angles should be equal, meaning that you will have to play with your pinion angle until the top and bottom U joints are bent the at the same angle.

With that much lift, you may not be able to get rid of the vibration without a cv and rotating your pinion angle.

I was able to modify the t/c flange of a drive shaft out of an 6 cyl tacoma with a cv at the t/c end. Then I used shackles to rotate the pinion angle. Ride hight just happend to work out perfect.

[fourwd1]

t96f said:

... longer shckles to bring the rear of the spring down and pivoting the yoke upwards. Slant cat axle blocks to put the yoke up.
quote]


NO

You do not want to point the diff up towards the t-case, UNLESS you have a double-Cardan joint at the t-case end of the DS (like the stock front DS).

You want the t-case yoke and the diff yoke to be parrallel in the horizontal plane.

t-case <------------------

-------------------------------> diff

where the < and > are the yokes and the DS connects between the two of them, and the -------- (dotted lines) represent parallel horizontal planes.


As long as they are parallel you can have a very steep angle (within the working capabilities of the U-joint) and no vibes. I know because I do and it took about a 7* shim to correct. Now no vibes at any speed.

[bayrunner]

Hey Guys ____ Thanks for the replies ,it looks like I,m going to have to get an Angle Finder and play with it . It seems to point in that direction. I,ll let you know What and How. ____ THANKS BAYRUNNER