Driveline Vibe Revisited (small question)

[Backdraft]

Ok guys,

Ive got a small driveline vibe on acceleration and deceleration around the 25-35mph range. I lowered the crossmember about a quarter inch and it still vibrates in that range. My question is since the vibe goes away at 35, is this something i shouldnt worry about or should i drop the transfer case a little lower and expierement more with that. Funds are preventing an SYE at the moment. Facts are 90 XJ, 4.0, AW4, 231, and 4 inch lift. TIA

Mike

[Kejtar]

what kind of 4 inch lift? If it's accelaration and deceleration I'd say that you're wrapping in the rear...

Kejtar

[Backdraft]

IT would be Rustys 4 inch leaf packs in the rear.

Mike

BTW, there are new shocks on the rear now and i double checked everything and its all bolted up good n tite.

[ChuckD]

Standard drop is an inch, and back to the Rusty's leaf packs, How old are they? If they have seen a lot of flexing, they could be giving you axle wrap like Remi said.

[Backdraft]

Very true. Thanks Remi and Chuck. These packs are used, and to my knowledge they were used for roughly 4 months. So as to the possibility that it is springwrap, I wouldnt think so at that age of use, but then again I have seen plenty of odd things. Ill go back into the garage and see about dropping the Tcase another 3/4 inch to total 1 full inch and see if that helps. If not, i have a guy near me that usually does all his own fabbing and troubleshooting. Hes pretty good at modified stuff but he is a CJ guy so dunno his knowledge of XJs. But hey, thats still a jeep:D

Ill keep you guys posted, and if ya have anymore brainstorms or oddities blurt em out, Ill take anything into consideration.

Mike

[Kejtar]

make sure that all the bolts are tightened right (ubolts, spring bolts and so on....)

Kejtar

[Backdraft]

Well, after making an angle finder (dont ask). I measured the pinion angle to be 54* on the rear end and the transfer case output angle(measured at slip yoke) to be 51*. A difference of three degrees. Im thinking some three degree shims ought to fix this nightmare.

Mike

[Backdraft]

Just an update to anyone who cares. I waited and waited on some 2.5* axle shims to come in after ordering them. Got em on today and no more vibes. THANK GOD
Only weird thing is, everyone I talked to said to put them in with the thick part to the back and that made the vibes worse. Reinstalled them with the thick part to the front and it solved my probles. Weird, but true.
Thanks as always fer all your opnions. Now all I need to do is raise the front another inch or so to get the thing level.(ass high)

Mike

[RCP Phx]

I dont no where you got your info from,but on a Non-sye the fat end Does go Forward(typically).

[Backdraft]

GRRRRRRRRRRRRR...........:mad:

Well isnt that just magical. Thats what I get for listening to other people instead of trusting my math. Oh well, I guess a little extra work doesnt hurt anyone.

Mike

[Kejtar]

Originally posted by RCP Phx
I dont no where you got your info from,but on a Non-sye the fat end Does go Forward(typically).
I think that depends wether it was a shackle lift or an AAL.... I Think a shackle would get the fat end forward to even out the angles, and the AAL would get the fat end to the back.

Kejtar

[Kejtar]

actually I just read that in the rear, the vehicle in question has 4" leaf pack.... now I'm kind of confused.....

Kejtar

[Backdraft]

However confusing it is, it rides pretty good now:D ;)

Mike

[dustin88]

I had the same problem after my 4 inch lift with aal and blocks, 4' shims, fat end to the back solved it. I dont know how yours got better fat end to the front. That does not make sence.

[Kejtar]

well it does if his leaf pack pointed the pinion up :D

Kejtar