I know this is an old thread but thought this could use clarification... There should be no problem using a selectable locker like an electronic or air locker in the front.

What you do not want to do is use a lunchbox/auto locker like an Aussie or Lock Right in the front.

If you did that, and you were in full time mode and you hit a slippery patch the full time mode would engage the front axle, then the auto locker would lock and you would lose the ability to steer and slide all over the place.

 

Yes, it's ***-backwards and a constant source of confusion (even 20 years on, lol!)

I mentally translate into "Land Roverese"
Part Time = Centre Diff Locked - slippery surfaces only
Full Time = Centre Diff Open - any surface

 

I have a '98 XJ with a 242 and 3" RE lift, and want to do an SYE as well to get rid of some residual vibration. Is it true I have to replace the rear driveline as well? If so, any recommendations would be greatly appreciated. Thanks in advance!

 

Very Good, Morat! It can't be simpler than that! How eloquent.

 

The only thing I have against the 242 in fulltime is with one wheel on ice, it just spins that wheel and you go nowhere. I really want a locker in my rear diff. I don't see a need for a front locker unless you're doing serious offroading.

 

Yes, you need a driveshaft with center splines. Tom Woods comes to mind.

 

Thank you!

 

Hack n tap SYE with a front driveshaft works fine.

 

Tom Woods sells a slip yoke kit with a replacement driveshaft. It's not cheap but it works great. I have one in my XJ.

 

Intermittent snow, rain, freezing rain, patchy black ice etc. So that means if your JEEP is a daily driver in winter months and you live north of Texas or in the mountains, then this 242 T case is a great choice. They are also great for towing trailers on variable surface roads.

I have put over 800,000 miles on several JEEPS equipped with 242's since 1994. I live in Canada where in the winter we are always fighting snow and ice from Nov 1 to May 1. I have had NP231's as well but I much prefer the 242 for my usage. One of my JEEP Grand Cherokees has a mild 4" lift and only see off road usage now. When offroad we are using the Part Time mode. One last thing, we have never blown up a 242 T-case yet either but then I don't set out to abuse them either.

 

https://www.motortrend.com/how-to/14...transfer-case/

This was in a V-8 powered ZJ with a 6.5" lift.

 

In swapping out the 249 to the 242 does it eliminate the knocking sound in sharp turns, I thought it was my front end, but was told swapping out TC would fix it do to the 249 having issues with that!

 

Never experienced any knocking with the 242s in either of my XJs. You can start to feel the u-joints as the turns get sharper, a slight bump-bump in the steering if you're going slow enough to feel it.