What the heck is causing this?

[hunterguy86]

Well I got my lift put on this weekend. I installed 4inch front lift springs, 4 inch rear blocks, new shocks and a raised steering arm. Now between 25-45 there is a vibration. once you hit 50-55 it goes away. I also noticed today when I was driving when you let off the gas there is a loud grinding sound. What would cause these issues? What should I check?


Thanks for the help yall

 

[supersize75k5]

the vib sounds like a drive line vibe,

did you get tappered blocks or shims?

when you lift it you change the angle and you can get a vibe in a certain speed range,


go to harbor freight or sears and pick up a cheap angle finder and find what angle the pinion is in relation to the yoke on the t-case.

some one will chime in on how many degrees difference it can have

 

[mciahpv]

You, my friend, now have bad pinion angle. The sound that you're hearing is driveline vibration. There's a great explanation of the whole thing here: http://www.4xshaft.com/driveline101.html

Basically, you're going to need to angle your pinion upward to solve for the bind you've put it in. You can do this with degree shims, beveled blocks or rewelded perches. A CV joint at the transfer case probably isn't a bad idea either. The bad news is, more work/money. The good news is, nothing catastrophic and a relatively easy fix.

Good luck...

 

[supersize75k5]

http://www.drivetrain.com/driveline_angle_problem.html

 

[rooferbret]

I had the same issue when i installed my shakle flip.
I lowered my transfer case and the vibe went away.
Unbolt the crossmember and take the 3/4 inch spacers and put them between the crossmember and the frame. vibe no more
Also, Get rid of the blocks and do a flip. You will love the ride.

 

[Leper]

Yes, driveline vibration. When you are slowing down, hit your break really hard and see if the noise gets alot worse. If so your yokes may be making contact.

 

[6.2puller]

If your blocks are tappered make sure they are in the right way. The thicker end of the block goes towards the rear.

 

[hunterguy86]

The blocks are tapered and the thicker part is towards the rear. This shouldve angled the pinion back up enough but I guess not. I was under the impression that 4 in of lift wouldnt change things that much to where I would have to rework my shafts.

 

[lamberthkp]

well i had that vibration when i put my 6'' lift on . i would try to move the spacers on the crossmember to lower the transfercase if you have not allready , that worked for me .

 

[hunterguy86]

Well I figured out what the noise was. I was lookin at my pinion angle today and it didnt look to bad. and then i looked at the tcase and noticed it was leakin from the front output shaft seal. Then i checked the tcase and it was low on fluid. So I changed the seal and filled it back up and that fixed it.