lostbuckaroo

Sorry guys don't mean to beat this subject to death but, I read lots of threads and did my research before posting... seams like each Jeep is specific. Any help would be much appreciated! Here goes my book. 98' XJ with over 200K miles, 5speed.. I bought it about a year ago.

So heres what I got...I Just installed a 2" zone AAL lift kit.. (Spacers in front not new coils)new OE replacement lower control arms, and I also replaced my old leaf springs with the Dorman Brand OE replacements..(because the old ones were shot) Thus adding the AAL that came with the Zone lift kit to the brand new replacement springs.. I know I could have just got a 3" lift with full replacements springs etc.. but I did my research and decided 2" is all I wanted..

Of course now I have some new driveline vibrations..but heres the kicker with the new OE replacement leaf springs + AAL combo I'm getting about 3-1/2" of lift on the rear it's got a definite rake...more than I'd like but I've read that the springs will settle and I'm hoping so. The vibrations happen at about 40mph then smooth out and come back around 60mph.. (however not as bad as at 40mph) while continuing to gain speed at 60+ mph although lesser the vibes never really go away...

Just to experiment I put about 320lbs (8 bags) of wood pellets in the back this just about leveled the Jeep.. and went for a drive...this smoothed out the vibrations a bunch.. not completely smooth like before the lift but way better... OK so I fully expected the vibrations however I wasn't expecting the excessive lift from the AAL and new OE springs.

Judging the the condition of the Jeep in general I'm going to go ahead and replace the U joints on the the rear DS... What else do you think I should do the smooth things out? Are these springs gonna settle or should I take the AAL out? Transfer Case Drop... ? I know a full alignment is in order as well.

pickles

I'd throw in some U joints and give the springs a few weeks to settle and report back.

Lyferxb9s

I have a 3'' zone lift with pretty decent driveline vibes now. I am going to install a TC drop and replace all my ujoints.

tvarney26

tire pressure? usually skipped over but easily checked, Balanced tires?
check all ur u joints on front axle front driveshaft and rear driveshaft. if all is sound check ur trac bar bushing if good check all ur tre on ur steering

lostbuckaroo

Thanks all! I think I'll start with the rear drive shaft U joints and report back! I know that if the springs don't settle much my pinion angle is going to be wrong... packing around the weight in the back is working for now but it's killing mileage. I'm optimistic but not sure how much the springs will settle in the winter temps.

VTJeep

Just for reference, there's only one joint in your rear shaft..Get a good spicer joint and see what that does. Assuming the front end isn't to blame then maybe a TC drop next. Your right on the cusp of "needing" a SYE, but for now I think just double checking joints, greasing all fittings (not too much!) balance, rotate if needed and get an alignment and probably be all set. Good luck man.

lostbuckaroo

thanks!

lostbuckaroo

Well guys still haven't done anything except leave the bags of pellets in the back... I looked last night and I had 9 bags in the back.. 360pounds... I took two out last night and drove it this morning... the vibes are about the same... but far better than when the Jeep is empty.. I'm going take all the weight out and see if it's "settled" any... I'm thinking not... I'm fear the combo of new OEM replacement springs and the AAL from zone is giving me to much height... the stance and the rake looks silly.. I'll post a pic.. So.. may just have to remove the AAL from the spring packs and wait till they settle ... How long did it take for your AAL's to settle??

OleBlue

If you take your AAL out you will be an inch lower in the back than the front more than likely. Then you will stil have an issue! If it were me, i would wait until the springs settle, its going to take a month or so with weight in the back. Put on a 1 inch tc drop and that will take care of your vibes.

lostbuckaroo

Agreed Old Blue...

Here's the numbers and the pics..
Measured from Center of the hub cap to the bottom of the fender flare.

Before Lift:
Front Left/Right - 17-5/8" aprox
Rear Left- 17", Right 17-3/8"

After Lift
Front Left/Right - 19-1/2"
Rear Left/Right - 20-1/2"

So the numbers after the lift 1" higher in the back ... doesn't seem bad but look at the pics..

First pic -Stock
Second - after lift loaded with 360 lbs in back
Thirst - after lift no weight in back..

lostbuckaroo

Driveline pics.

Thank you for you all's help... Really appreciate it... Gonna install new U-Joints this weekend.. inspect motor/trans mounts and go from there.

Potatowalker

I just did a rubicon express 3.5 kit with new rear springs and i got about 4.5. I had pretty bad rear vibes and a bit of a rake. I tossed all my tools and crap in the back and a month later it's just starting to settle down a bit. I took my rear driveshaft off and replaced BOTH of the U-joints. One was completely dry and rusted inside but looked fine from outside and didn't have any noticeable play. When I replace those and put it back on (remember to grease the slip yoke liberally) it got rid of almost all my vibes. The little ones that were left have mellowed out as the springs are settling. I did a 1" TC drop to start and will eventually be adding a SYE but for yours you might be fine once you get things all refreshed on the driveshaft. What I'm getting at is even if it doesn't look bad, it could still be a problem so replace what you know will wear anyway and start fresh. It has 200K on it so likely new U-joints will make a noticeable difference, plus you'll know they're good to go!

Potatowalker

This looked and felt just fine from outside but was clearly on it's way out and not running smoothly once I got it apart! Once I got it off I could definitely feel there was some play on the caps that I couldn't feel with it still on the jeep...

lostbuckaroo

Will do the joints tomorrow! Thanks bro!

ColoradoCorey

ok just from looking at the DL angle it seems you need to shim your axel up. It looks like the pinon is pointing straight forward with the T-case alot higher.