Same thing with mine. It goes so much smoother in neutral. Does yours have the D35 in the rear? I must have a trac-loc or whatever cuz mine is definitely a posi. Some people say they aren't posi, and some say they are. All I know is that all 4 of my tires get equal power in part time and I leave nice twin spin marks on gravel roads without even trying to in 2wd.

 

I never saw the point of this crap anyways. Obviously Jeep didn't either past 91. The axle internals are turning all the time anyways but the driveshaft is not. On my truck in auto mode, the front shaft spins. All wheel drive blazers from the 70s don't even have hubs and all my 4x4s had the hubs locked at all times cuz I was too lazy to get out and disengage them anyways. I never had any extra wear problems or problems of any type

 

It's what the manual says and it works fine. Never expereinced a hiccup. If it was bad to do, I'm sure Jeep wouldn't have touted it as "shift on the fly" and wouldn't have put the instructions in the owners manual that statted " any legal speed".

But, if you have an axle shift motor/vacuum issue this can change.

 

I was under the impression that only non disco equipped XJs were "shift on the fly". I'm not sure speed limits were up to 75 when these things came out btw

 

Nope. The were shift on the fly always, since 1984 except for one transfer case that wasn't around long. Vacuum actuated like an AMC Eagle.

Speed is not an issue. 55 vs 80.

 

It was stupid, had no real benefit and cost more money. Not to mention the shift forks that would bend in the CAD, the poorly machined splines that the slider would stick on to and not allow the front axle to engage. And then there's the vacuum harness that got douched with engine oil at every change, swelled all up and didn't seal well. Other than those few minor details, they were *****in'.

 

I have noticed from scrounging around the SY that some of the older v6 equipped XJs had no disco. In fact the only ones I think I've seen are Renix 4.0s with the 231 T case

 

You saw the ones I'm talking about that were full time. Rule of thumb til 91 was full time = no disco, part time =disco.

 

What do u mean by no disco and disco

 

Central axle disconnect.

 

Unless you have lockers, all of your wheels wont get equal power. Cross a deep ditch diagonal and you'll see.

 

bam! that answered my question. thanks dude

 

haha, no prob man. Thats why yours always says part time. You don;t have the full time option. Take a look at the tag on the transfer case. It should say "new process gear" over the top and a "231" on the middle line. Google a picture of an NP231 transfer case tag and get a better reference, then check yours.

 

It might also say a different name similar to "new process gear" because after 97 the company changed it's name or got bought out or somethin like that. It should still have the "231" though.