Whats Best 99 XJ suspension swap?

[KennyB]

I am going to rebuild the 99 XJ's suspension....it has a hillbilly home brew lift on it now...And it is all worn out!! Rear leaf sprngs are totally flat...

.it is all going---- all springs and shocks---all bushings--steering stailizers, steering rods, tie rods and ends...ball joints ect...all new----

---going to rebuild both diff and install lockers in boht also.. I want to rework the entire suspension and do a 4.5 inch lift.... Want to install the best one I can...This truck will be driven on the street as well as hittin the trails.... Im looking at runnin 33's on it also.... Any Ideas??? i have a list, but want some opinions form the masters that have already doen this....

Thanks
Ken

[jugbutt]

What ever you can afford!
Sounds like you got a plan.

[firehawk]

I'm no master, but I've lifted mine, and had to go back and replace/add stuff I THOUGHT I could get by without.

I can't remember...does the '99's have the HP front axle? My '00 didn't and after screwing with pinion/caster angle problems I finally bit the bullet and pulled the LP axle and bolted up a HP axle.

At 4.5" you will need an SYE on the rear driveshaft/transfercase. If you have the 242 TC a good way to go (maybe the only way) is the RE Hack & Tap SYE. You can run a front driveshaft on the rear with that setup.

Replace the flimsy factory tierod too. There are many out there, I happen to run a Big Daddy tierod. Running 33's the stock tierod will flex making the Jeep want to wander.

You'll need an adjustable trackbar to recenter the front axle too. I would look into one of the many HD trackbars out there that include a new HD mounting bracket. DO NOT get a trackbar with a TRE in the frame end like the stock one.

Just my opinion, but I'd steer clear of the poly bushings. They crack, and will squeak. Stick with the factory style rubber bushings on everything. Again, just my opinion.

As far as a lift kit goes, there are a bizillion out there. I suppose which one you get will depend on how much you're willing to spend.

As of now, I have no experience with lockers. Someone else on here that has experiece with them should chime in on this one.

[muddeprived]

99's have HP dana 30's if i'm correct. Our 00-01's are low.

[96xj]

with a 4.5 lift I dont think you need to have a SYE
SYE is if your running anything above 6.5 lift

[muddeprived]

with a 4.5 lift I dont think you need to have a SYE
SYE is if your running anything above 6.5 lift

Probably 85% of the jeeps lifted 4.5" or higher have a SYE kit, or at least a dropped t-case crossmember. SYE kits are need with as little as 2" of lift sometimes. When I put my OME 2" lift on, I had to get a SYE kit to eliminate my vibes cuz the transfer case drop didn't do the job.

[firehawk]

Probably 85% of the jeeps lifted 4.5" or higher have a SYE kit, or at least a dropped t-case crossmember. SYE kits are need with as little as 2" of lift sometimes. When I put my OME 2" lift on, I had to get a SYE kit to eliminate my vibes cuz the transfer case drop didn't do the job.

Same here. :thumbsup:

[Mudderoy]

with a 4.5 lift I dont think you need to have a SYE
SYE is if your running anything above 6.5 lift

I have read that you "may" need a SYE for a 4.5" lift or higher. Some XJs can get away with a tcase drop, some cannot. I have also read that even if you don't have bad vibes and a lift of 4.5"+ that over time you will mess up the u-joint on the rear drive shaft.

I don't want to be limited to 4.5" lift, also I want to make sure my rear drive line doesn't bind when off road, so a SYE is in my future.

[KennyB]

YP---SYE will be part of the package too...Ill probably do the Transfer case drop also.... I am gonna invest the cash and do it right.... sHES GONNA GET BEAT A BIT, BUT I want the suspension and mechanicals to hang in.... and be able to drive home.... :):):)

But ill post on what I do to it and what it does.....

Thanks for the info ---ya;ll are all GROOVY CATS!!! Appreciate it:patriot:

[muddeprived]

YP---SYE will be part of the package too...Ill probably do the Transfer case drop also.... I am gonna invest the cash and do it right.... sHES GONNA GET BEAT A BIT, BUT I want the suspension and mechanicals to hang in.... and be able to drive home.... :):):)

But ill post on what I do to it and what it does.....

Thanks for the info ---ya;ll are all GROOVY CATS!!! Appreciate it:patriot:

You won't need a t-case drop if you do the sye. It's one or the other, or the t-case drop until the sye.....

[Cobrajay]

Probably 85% of the jeeps lifted 4.5" or higher have a SYE kit, or at least a dropped t-case crossmember. SYE kits are need with as little as 2" of lift sometimes. When I put my OME 2" lift on, I had to get a SYE kit to eliminate my vibes cuz the transfer case drop didn't do the job.

+1 I just went 4.5 and the transfer case drop still gives some vibes. Gotta get a SYE

[2000XJ]

with a 4.5 lift I dont think you need to have a SYE
SYE is if your running anything above 6.5 lift

A SYE or Tcase Drop is really XJ specific. Some XJs need one with something as simple as a BB, and others don't need one until 5.5" of lift. Rule of thumb is that the '97+ XJs should get a SYE when going with 3.5" or more of lift because it will just take care of any driveline vibes right off the bat.

A tcase drop may suffice in many situations, but at the same time you're dropping your tcase an inch (sometimes more sometimes less) to fix a driveline vibe - this chews up ground clearance. With a SYE you're not losing any clearance.


YP---SYE will be part of the package too...Ill probably do the Transfer case drop also.... I am gonna invest the cash and do it right.... sHES GONNA GET BEAT A BIT, BUT I want the suspension and mechanicals to hang in.... and be able to drive home.... :):):)

But ill post on what I do to it and what it does.....

Thanks for the info ---ya;ll are all GROOVY CATS!!! Appreciate it:patriot:

Like Mudd said, it's either one or the other, but not both.

My best advice is to figure out what your budget is, ballpark, and add $1000 or so to it. For a 4.5" lift, you can't beat what Rubicon Express has to offer. Their springs are great, their kits are very complete - you get what you pay for, and you pay for everything, so that's what you get when you open the boxes.

You say you're going to rebuild the diffs - there is no sense in doing this unless you're going to regear. It's way too much of a headache to pull everything apart, take all the measurements, get the right tools, and then re-set the gears to the proper specs. Unless you're going to regear the axles, avoid this - there really is no need. A good diff fluid change will suffice.

If you're going to go to 33" tires, then consider regearing your rig. You'll probably want to go with 4.56 gears. In this case, rebuilding the diff is necessary as you will need new carriers, pinion gear, ring gear, etc. This is the time to do a locker. If you're doing lunchbox lockers then waiting to regear isn't necessary because you can just do them yourself without having to worry about changing any of the specs in the diff.

Best way to go about doing this is to save up your cash, do your due diligence, gather the parts, and spend a couple weekends wrenching so that you have the least amount of downtime if this is a daily driver.

Not trying to scare you, just trying to say it how it is. Many of us have been there, and know what the financial committment is like. It sucks to have a rig that is only partially done because you didn't account for everything. This is why I said to add an extra $1000 to your budget for a build like the one you described - you're inevitably going to not take into account certain things that will add cost to the build - this isn't your fault, it happens to all of us.

[KennyB]

No worries--fully understand the info your giving me...Im not afraid of it.... I am a Steam Turbine Field Service engineer for Siemens Energy... Have worked on all my old vehicals and bikes all my life.... But in the area of lifts and such I am understnad the concept but i also understand all of you have done it,,,thats why I ask...I really appreciate the advice/// Especially on the slip yoke or transfer case drop.... I actually would like to keep as much tucked up under the truck as i can...But it dropping the case, works better than the slip yoke...thats what I am going to research more... As for the rest,,, as for my budget,,,its pretty high....been saving and sold one of my old honda cb750 choppers,,,added that to it. But i really do appreciate the info...soon as I get off this job in nebraska at a Nuclear plant,,,Im going to start gathering up my kit, and everything i want to start on...Ad fas as the diff's...I want them to be snug,,,Ill open them up,,,check the actual ring gear and pinion backlash, and go form there,,I may very well regear at the same time....Everything I read on jeeps talks about how they regeared..
,I want all new seals, ect... and Ill do lockers for sure... , also like I said all new drive shaft parts ect....I want her tight and snug----proper alignment

Again,,,the information is appreciated and invaluble!! It seems I ask the right folks!!! Thanks again

[2000XJ]

The SYE is really better than the tcase because once its done you can have whatever amount of lift you want and avoid driveline vibrations. With a Tcase it only works until a certain amount of lift before you may run into driveline vibes again.

[Mudderoy]

The SYE is really better than the tcase because once its done you can have whatever amount of lift you want and avoid driveline vibrations. With a Tcase it only works until a certain amount of lift before you may run into driveline vibes again.

And, I may have already said, the longevity of your u-joints increase. During articulation binding can occur, at least that is what I have read.

[COSXJFAN]

FWIW, my 87 XJ has no SYE at 6+" of lift, and no vibes. I do have a T-case drop kit, and I don't notice a lot of issues with ground clearance. My u-joints last fine, but I do not DD mine either. HTH!!