rear drive shafts

hey guys Im researching rear drive shafts and I have come to what many may consider some silly questions however...

the stock jeep xj comes with a rear drive shaft with a slip yoke on the tc.

I have a 242 TC and im curious if this design works stock....What stops us 242 (or any others) guys from using a new double cardan rear shaft thats built to length for our suspension?
I understand the sye kits transfer stress to drive shaft rather than the slip yoke and TC output bearing, and it transfers the slip to the drive shaft however if this is a viable working stock engineered set-up..... What stops a lengthend double cardan (for vibes) built rear drive shaft from replacing this issue other than maybe limiting straps ? ( of course aside from my already listed reasons for a SYE)


Thank you for your help

are you asking if you can run an SYE on a stock rig and a driveshaft with a slip/spline?

if that is the question the answer is yes. its unnecessary, but it will work.



if you are asking if you can run a non-SYE tailhousing with a fixed length double cardan shaft on a lifted rig, the answer is no.

Keep in mind that when the engineers designed the driveline the parameters for operation where dirt or gravel roads and city streets. They had to allow for maybe 8" of articulation and a slip yoke on your 242 that may see .25" of horizontal travel. Lift the truck, go offroading like many of us do and your easily doubling those numbers and adding the torque loading that happens as the slip splines travel out on the output shaft. Will it work... kind of, on city streets... will it work offroad, maybe for a little bit. A non double cardon shaft like your rear is currently has a better chance of surviving but the transfer case output will end up paying the price.

Im essentially asking what I can get away with by changing the style of the rear drive shaft.
As of now im running a 3.5" RE lfit and used 1" drop bracket spacers on the tranny cross-member . My TC is a 242 so Im not wanting to hack and tap the out put and the Tom woods conversion Is 800$. So no Im not trying to run SYE on a stock Xj but I am trying to use the Stock setup with the drop brackets and hopefully avoiding an SYE output shaft.

There is nothing wrong with using a hack n tap on a 242, much better solution than a "wreck you're motor mounts" TC drop, I prefer a yoke style SYE as you can use the same style driveshaft front & rear. Good luck.

If you need an SYE, you need it. Your three options are Hack and Tap SYE, Tom Woods 242 SYE, or swap to an NP231 and install an SYE.

I've been running a hack and tap on a 231 for years. never had an issue.

I wouldn't hesitate to run one on a 242. 800$ is way not worth it. thats pushing 241 money.

I ran a hack and tap on my 242 for years, no problem

has anyone bought a new output shaft and had it lathed and tapped?

Im not keen on drilling into the shaft as its my DD and only ride. If the threaded hole is offset I would hate to have the shaft crack and be stranded.

4x4JeePmaNthINg said:

has anyone bought a new output shaft and had it lathed and tapped?

Im not keen on drilling into the shaft as its my DD and only ride. If the threaded hole is offset I would hate to have the shaft crack and be stranded.

Click to expand...

Or your rig might get hit by lightning & just split the shaft!
Just joking, there are probably Millions of Hack N Taps in use out there & I've never heard of a shaft cracking like that.
You can always use one of these http://www.ironrockoffroad.com/10197.html to make sure its centered.
Installing a hack n tap is easy, Just go slow & use Lots of oil, I put 1" of motor oil in a small glass & keep dipping the drill bit in it as I drill & then do the same for the tap, Go Slow with the tap, In 1/2 to 1 turn then back out a little bit, after a couple of turns I remove the tap, clean out the chips & dip it in the oil & continue; make sure you keep the pressure on the tap even.
Good Luck!

4x4JeePmaNthINg said:

has anyone bought a new output shaft and had it lathed and tapped?

Im not keen on drilling into the shaft as its my DD and only ride. If the threaded hole is offset I would hate to have the shaft crack and be stranded.

Click to expand...

the hole on mine isn't even remotely center or straight.

its held up for years.

putting it in a lathe to part the shaft and drill it would be the "best" way to do it. but many people do not have access to one. i did my 231 hack and tap with the Tcase still installed in the jeep. my recomendation is to purchase quality drill bits and a tap for the job.

also, my bolt is slightly off center. not issues with vibration or retention. the bolt is simply locating the yoke, the splines see all the load. if the bolt is experiencing a load, your shaft is too short. one could make the claim that it unbalances the shaft, and i would agree... but its not enough to notice.

4x4JeePmaNthINg said:

has anyone bought a new output shaft and had it lathed and tapped?

Im not keen on drilling into the shaft as its my DD and only ride. If the threaded hole is offset I would hate to have the shaft crack and be stranded.

Click to expand...

The yoke is held center by the splines, and the bolt in the middle is just to keep it from falling off. It doesn't require precision machining.