Baystate Jeepers

Hello everyone,

I am currently new to the jeep game and looking for some advice. Recently installed a 4" RC lift kit on my TJ and now I have some vibration. My mechanic told me that I new a SYE and drive shaft. Not too concern about that but I was also just inform that my TJ currently has the wrong transfer case. My mechanic told me that the transfer case is off an XJ.

I found a transfer case with a SYE and plan on buying a Tom woods drive shaft. My question is, since i am replacing the whole transfer case and rear drive shaft, should I also replace the front one?

Also, I live in the north shore area and looking for a place that can do the work for me. Looking for a good shop that will not rip me off?

Looking for advice and suggestion. Thanks

I believe both the TJ and the XJ ran the np231 T-case. When you lifted it you had two options, To put in a T-case drop to help with the angle of the drive shaft or do the SYE and new shaft. Its not really hard to change out the T-case , if you know how to use wrenches it can be done in the driveway. The front shaft always seams to survive this vibration as its a High pinion which reduces the angle. If you want to change it , Tom Woods make a really good product. Good luck FjR68

Thanks will be getting the parts soon.

I have a NP231J with a Advance Adaptors SYE for $300.00. Came out of my 1995xj as I went with a Atlas 4.3 a couple years ago. Good shape. Should be the same a a TJ. If interested email me @ >>easterncalibration@verizon.net <<

I believe some XJ's had a slightly different clocking on the t-case, but that would only affect the front driveline. The rear output would still be in the same spot.

I think the XJ / TJ clocking difference is on the tail housing of the transmission, not the transfer case pattern.

I saw Nilson's t-case and it has what looks like a damper on the output. Like you'd see on a 4-cylinder engine crank shaft. A mechanic told him that's the source of the vibration and IIRC, that same mechanic said the t-case wasn't original, that it came out of an XJ. And maybe it did, but my XJ doesn't have one. I took a ride in Nilson's rig and it seems to be typical DS/u-joint vibration. It's bad when you accelerate, but eases up when you let up off the gas. And oh yeah this vibration wasn't there before the lift so blaming the vibration on the t-case seems like a stretch

The vibrations started after a new 4" lift with t-case spacers. I'm guessing the spacers are an inch and a quarter or inch and a half, they might be 2 inches but I don't think so

I think you're referring to the slip yoke grease boot. Any suspension changes can cause the drive line to be finicky in a Jeep... If he hasn't installed an SYE / double cardin DS then it is probably the problem is the slip yoke, even with t-case drop spacers.

AFAIK the front DS will already be a double cardin style with a fixed yoke for all Jeeps so it shouldn't require replacement.

What about adding a MML? From my understanding a MML will help with the DL angle.

I had the dampener on my setup.

ngarc83 wrote:Hello everyone,

I am currently new to the jeep game and looking for some advice. Recently installed a 4" RC lift kit on my TJ and now I have some vibration. My mechanic told me that I new a SYE and drive shaft. Not too concern about that but I was also just inform that my TJ currently has the wrong transfer case. My mechanic told me that the transfer case is off an XJ.

I found a transfer case with a SYE and plan on buying a Tom woods drive shaft. My question is, since i am replacing the whole transfer case and rear drive shaft, should I also replace the front one?

Also, I live in the north shore area and looking for a place that can do the work for me. Looking for a good shop that will not rip me off?

Looking for advice and suggestion. Thanks

The trans clocking is different.
TJs could (not will, but could) have a damper, late XJs 97 later WILL have a boot.

We have a t-case here, SYE installed, for sale, cheap.
We're a Tom Woods dealer, many drive shafts in stock.
We also have or order adjustable upper rear control arms, and you will likely need to adjust them to go from one drive shaft to the other style.
TJ D30s are low pinion, unless an HP D30 was swapped in.

We do all of that work, all day, every day.

The front drive shaft only needs to be replaced if there is damage so significant it is cheaper to replace than fix. Another reason our customers replace them with an SYE kit and rear shaft is simply peace of mind. Tom Wood REALLY offers a great warranty on a great shaft, and their gold seal u-joint warranty cover your shaft, too, in the event of u-joint failure.

That being said, we usually like to see the vehicle and inspect the vehicle to quote a job, as well as help make sure you're on the right track. 97-02 TJs are showing up with rotted frames more often than not, and we have seen them with new vibrations after lift kits were installed because control arm mounts are cracking and failing. Looking at the whole vehicle first ($80) or at least a quick eye on it helps make sure your priorities are straight on your project.

Thanks everyone for the info. I already installed a new transfer case with sye and new drive shaft. All my vibrations are gone.

10 degree difference found in the transmission flanges. 13 degrees vs 23 degrees.
Front drive line is affected, and 4wd shift linkage is affected.

It makes a bigger difference when installing an XJ trans into a TJ, because of interference with the tranny skid.