97-01 driveline vibes. Your solutions???

[Ray H]

Without a CV shaft, the pinion angle should mirror the output shaft angle. If you have -1* on the output shaft, your pinion should be about level (to compensate for a 1 or 2 degree rise under acceleration). Add 4* shims to the rear, not to raise the pinion, but to lower it. The thing with Cherokee leaf springs is that the springs are longer behind the axle than they are in front of the axle, so when you put an arched (lift) spring on, the axle is positioned towards the front of the arch which tends to point the pinion towards the output shaft. If you arent running a CV shaft, you need to shim the axle down to match the output shaft angle. The only reason I mention this is because some people are under the impression that the axle should always be shimmed UP when in fact (I should say "in principal"), to get the ideal angles for a nonCV setup, the pinion should be shimmed DOWN.

Theres a problem with shimming the axle down though. Its DS length and ujoint angle. If you are lifted high and running the stock DS, it probably wont be long enough with the pinion level and your ujoint angles are going to be higher.

 

[Ben H]

97XJ 6" on 34's 200K
1" TC drop and tons of vibes, but I just turn up the radio
I have some 4* shims but I havnt put um in yet

What are the repercussions of not fixing the vibes? So far I havnt seen any and I wheel the hell out of my Jeep. Got 30K with the vibes.

Stress on your drivetrain, all components. And driving a vibing rig.:cheers:

 

[DaveD912]

Theres a problem with shimming the axle down though. Its DS length and ujoint angle. If you are lifted high and running the stock DS, it probably wont be long enough with the pinion level and your ujoint angles are going to be higher.

This is the problem I had with my '99 at 3" of lift. I was able to get the angles correct, but didn't like how far the axle was pulled out. I went with an SYE.

 

[anotherjeff]

This is the problem I had with my '99 at 3" of lift. I was able to get the angles correct, but didn't like how far the axle was pulled out. I went with an SYE.

i was thinking the same thing. i actually put the 4* shims back in and shimed the diff down today. still had a very slight vibration on acceleration, but it seemed (like dave said)the DS was pulled way out. I'm done with the shims and the t-case drop. they were inexpensive and all i'm out is my time and a few bucks. i'm ordering the SYE this thursday am.

 

[anotherjeff]

Ordered a SYE from PORC Friday at 4:30 and got it Sat. after lunch. Talk about fast shipping. I'm going to install it tomorrow.

 

[Mtb Jak]

how much was the SYE?

Im thinking of undertaking this same lift with the a 2000 sport 231

full packs but the way the jeep looks at first all jacked up is making me a little weary of it.. has it settled??

all in all how much has the lift+shims+tc drop+SYE cost if you dont mind me asking!!

 

[anotherjeff]

how much was the SYE?

Im thinking of undertaking this same lift with the a 2000 sport 231

full packs but the way the jeep looks at first all jacked up is making me a little weary of it.. has it settled??

all in all how much has the lift+shims+tc drop+SYE cost if you dont mind me asking!!

it was a little harsh at first but after about 50 miles the springs and shocks start 'breaking' in and to me drives as well as before. i helped the the rear settling process along by driving around for the last 2 weeks with 2 #80 bags of concrete in the back. to date the back has settled in to about 4.5 inches and the front sits at about 4.25 (with an extra stock insulator).

as far as the price goes, i'm sure you can do a lift and SYE for a lot less than i did. i bought the stuff that i wanted and suited my driving/lifestyle. I didn't buy AALs cause i tow a trailer with a couple of ATVs on it every now and then and every set of AALs i've used (long or short) sag with even a little weight. I also wanted components that wouldn't have to be replaced in 2 years due to wear or sag (RC and Rusty's springs Skyjacker lower control arms).

So, to answer your question honestly i'm in for about $1300 to date (including the alignment, paint, fluids hardware and sealants)

this is most of the stuff i bought so far:

RE super ride with full packs-696.00 shipped
Procomp trac-bar 120.00
PORC's SYE 196.00 shipped
steel 4* shims i bought at a local spring shop for 20.00
'99 HP30-100.00
'97 (?) frt ZJ DS-50.00
DT steering dampner-38.00
extra set of stock front spring insulators-22.00
set of MJ shackles for 5.00 (didn't need them but it was a sweet deal).

 

[anotherjeff]

8+ beers and 6+ hours and the SYE is in. i will never question putting a SYE kit in ever again. no vibes. no noise. butter.

 

[Ben H]

The front drive shaft worked for you? Nice job on the install, it looks very clean.