lift problems????

Hi, I could use some help... I lifted my 97XJ a while back and used a superlift 3" kit. it cam with full leafs and coils, new LCA and the shocks. after the lift came a whole bunch of vibrations...I found out that the rear drive shaft was pulled out a bit and had DTS (drive train specialist) lenghten the Drive shaft and correct the pinion angle, and while they had my jeep i also had them install a limited slip in the rear. They told me that the axel shims were incorrect and removed them. I still have bad vibrations during acceleration between 20- 35 mph...then it seems to go away. also i have what i can describe as a the sound of huge mud tires, but only have 235BFG AT's that i had befor the lift. Could the new bushings in the LCA and the rear leafs cause more sounds???
what about hydro shocks vs gas shocks????

So far in this project I have replaced the folllowing parts: All the tie rod ends, the LCA, track bar(with a stock one), drag link, steering stabalizer, shocks, coils, leafs, and made some front SB link extenders.

My question is how can i get rid if the vibrations???
I was thinking that the pinion angle in the front may not be correct, or maybe the rear may still need some adjustment. The trac bar may need to be replaced with a Rusty's adj one??? Could the LCA length be off. I set the wheel base at 101.4
any rate i hope that someone can help with these problems...
Thanks
Dave

Since you dont have adj. upper control arms to adjust your pinion angle I would start by shortening your lowers a little at a time to see if the big tire sound go's away. Or you could just pull the front DS and make sure it is really coming from that. As far as the rear if you have the chrysler 8.25 it is nearly impossible to get rid of ALL the vibes unless you invest in an SYE and CV driveshaft.

Did you replace all your U-joints when you lifted it? I have seen a couple of times where the higher angles on an older U-joint can cause them to fail real fast after putting a lift on.
Also it could be the angles on your front end.

I would look into an AA HD SYE.

I had nearly the same lift you have, on my 97 and i had the same vibe problems you are describing. In my case it was my front drive shaft. Try taking yours off and then running it on the highway for a short jaunt. In my case it became plain as day that my front shaft vibrated like hell. Problem is that your pinion has to be pointed directly at the transfer case in order for the Double Cardan joint in your driveshaft to work correctly. Short of adjusting your upper control arms (which may screw your caster anyway...) the only way to fix it is to have your axle tubes cut and rotate the front pumpkin to the right angle that you need. This solved my problem and only cost me $200 CDN at my local axle shop. I am currently VIBE FREE...
Buck

ya, i did replace the rear pinion seal , the axel seal, and both u-joints. in the rear.
no i have not looked into the front drive shaft...but it sounds like a good idea.
did you have the "polyearthane" bushing??????( bad selling, sorry)

Buck,
did you have to mess with the trac bar?
what about the LCA'sdi you have to set the length on them?, or the rear pinion angle???
did you buy a superlift??? are u happy with the shocks? did you replace the ones that came with the kit?

My kit was a Black Diamond 3" add a leaf, it came with longer front coils, longer lower control arms, add a leafs, a park brake extension bracket, new shocks and new bolts all round. The kit told me to redrill my track bar mounting hole on the axle end by 3/4" towards the driver's side of the vehicle, so I did (regrettably). Overall, the kit sucked. I don't think its available any more since Black Diamond has changed hands since i bought it (1999). The front coils were ridiculously stiff, shocks were too firm, trackbar redrilling thing was stupid, rear add a leafs were stiff and noisy (squeaked like a sack of mice). The control arms were also cheaply made: fixed length and one end had a plastic bushing - lasted about 30000kms, other had a rubber bushing - still good when i sold them, after 60000kms. I ended up taking out the AAL's and having my springs re-arched at the local spring shop. Later I took out the coils and went back to stockers with a 2" spacer. Then i changed the track bar to adjustable (custom made locally for $45), and went with Rancho 9000's. Of course that was a million mods ago, but since mine is mostly a daily driver, my goal was and is capable comfortable off roading on muddy steep rocky inclines surrounded by giant cedars, and comfortable, predictable on road performance ( i still gotta use it for groceries and cross country trips with an angry wife and farting children). Now, my set up is perfect for my uses (3.5" with 32s): custom front coils and spacers and bumpstops, custom lower and upper control arms, custom skids all around, custom bumpers, racks and custom rear springs. I'm now running doetsch tech shocks and i am totally happy with everything. I just recently put in a Hack n' tap (thanks forums for your support!!) SYE and double cardan rear drive shaft. Its perfect for my needs. My entire current package cost me about $2200 CDN, which is a hell of a lot less than if i had bought all aftermarket parts.
Hope that helps,
Buck.

I forgot to mention that before i decided to change lifts, i first eliminated the front driveshaft vibes by making a drop kit for my transfer case. I scrapped the xcase drop later and went with having my front pumpkin rewelded to the axle tubes because i did not want to lose that precious inch of underbody clearance.
Buck.

thanks, i will look into these ideas...
dave

removing the Front Drive shaft

is it easy to do? and should i replace the ujoints too??? any thoughts?
at this point i am gonna do lots of reading befor i do any more work to my jeep, its costed me a pile of money and i still am not happy with it.
If i can get the rid of the vibes and get it to ride like it use to and also get better gas mileage i would be happy. by the way, has any one else noticed a huge drop in gas milage after installing a lift?
mine droped to about 12mpg...that sucked. after i made the LCA's longer it got a little better, but i think that it could be a lot better. like maybe in the 18-20mpg range? is that possable?
dave

Re: removing the Front Drive shaft

Driveshaft is a piece of cake to take off. You don't need to replace the ujoints (unless they are worn).
Unfortunately, vibes are often just part of the package of lifting your jeep. I have heard from enough people to know that my experiences are unusual --- usually people end up with some vibrations after a lift. The gas mileage thing is weird though...i have not heard of that, my own mileage went up after i lifted mine and put the larger tires on (due to the fact that with each revolution of the wheel you will travel slightly more distance than with the smaller tires). Of course it went back to normal when i changed my crown and pinion gears. The only thing i can think of is that perhaps you are compensating for the loss of power (due to having larger tires) by working the gas pedal a bit too hard? Regearing is hard to avoid if you still want that stock feel. Good luck with it eh?
Buck.

Well i would think that to be true if i had bigger tires, but i have 235 75 r15's on stock rims?????
Dave

You're right davberry, if you still have stockers on stock rims, then the mileage thing is weird, I'm fresh out of ideas....anybody else have a few cents to put in?
Buck.