8.8 and vibe ?

[Preacher]

Here we go.....


While driving my TJ, I noticed a sound from the passenger rear wheel area, that almost sounds like a "severely cupped tire" between 10-20 mph while slowing down (not the tires as I had them replaced 20 miles ago) I Jacked the vehicle up and placed the rear axle onto jack stands, had a friend put the vehicle in gear till it reached 25 mph and then let it slow down on its own. During this process I now notice the same sound but more amplified, almost a knocking sound, that disappears below 15 mph and under acceleration, as I am now able to pinpoint the noise to somewhere behind the passenger side wheel. Both sides of the axle with tires on, I can grab the top of the tire and the bottom and cause a slight movement (causing a a faint "clunk" sound also). This is a 8.8 rear axle with only 5,000 miles on it. Could the outside bearing on both sides be wore out with it being more noticable on the passenger, or is there some "tolerance" up and down from the factory (there is also no movement side to side)? I have pulled the rotor on the passenger side, took a look at the outside bearing, "appears" fine, not leaking either. So what would you look for? It makes the sound with or without the wheel and tire on, just more noticable with it on.

This again is a new axle, not rebuilt.
True-Trac w/4.11 Gears
Full of fluid and always has been.

Second question.

Went from a two inch coil spring lift to a RE 4.5 SF/SA kit
As heard in many forums before, I now have a vibration upon maintaining speed and slightly during acceleration at speeds greater than 40 mph.

I have set the pinion angle inline with the rear CV shaft (SYE installed prior)and 1, 2, 3 degrees below, and the same above to rule out pinion angle with no noticable change. It is currently set 1/2 degree below with vibration still present, what I am curious about is can the offset of the 8.8 (to the passenger side) combined with that lift height cause a vibration such as described, and if it can, how can you adjust the components to lessen that angle (angle caused by passenger offset).

Specs on vehicle

2001 TJ
4.0 w/ Auto
4.5 RE SF/SA Kit
1"BL and 1 " mm lift
Flat skid with appx. 1-1/2 lift
30/8.8 both true trac'd w/4.11s'

Let me know what you guys think, Im getting tired of messing with it. (it's week two and my DD)

JR
_________________
AKA "PREACHER"

JC4ME-----> w/o Christ, I'm nothing.

 

[Down&Dirty]

Are the brakes rubbing? Since you pulled the bearing, how did the splines on the axle look? What happens when you hold the driverside tire still and move the passenger and vice verse?

As for the driveshaft, tom woods told me that I would encounter problems with a RE3.5 SF and a flat skid plate. With the 4.5 you could be in for more problems. Did you get the driveshaft ground for extra clearance? I don't think that an 8.8 is offset enough to matter to much. The main problem is that you really need to run the super short SYE or strech the wheelbase a little.

 

[Preacher]

Brakes not rubbing as far as I can tell, both sides of the axle regardless of which side is held and which isn't, has the same play. Checked a friend of mine who had an 8.8 sitting in the shop, and it had the same play up an down as mine, so maybe its a factory thing. However I know the sound I hear is definitely abnormal.

Far as vibes with the superflex lift, I've known a few people who had that lift with no problems, but I may see if TW has any ideas. If not Zubz, you may have a TJ sitting at your shop on Sat. I've been told it's a jeep it'll have vibes. Rough ride I can handle, but knowing my u-joints and driveline taking a hit is not cool

The drive shaft isnt at a bad angle at all especially with the mm lift, it seems like it ought to be smooth like butter........