part time light

[90xj06]

on my 90 when i put it in 4wd the light comes on... normal.
here is the question if i go from 4 hi to 2 hi that dissconnects the transfer case. but leaves the axle "locked". do i have to immidiatly go to reverse to unlock the hubs or can i just drive and get to it later?

[ebxjbob]

On my 88, 94, and 96 it was just shift in and out on the fly and drive, or so I thought

[90xj06]

i dont know. but i think its the vacuum disco. when i go around a turn sharp enough it makes the disconnect sound and the light goes off. if it is the hubs just staying locked. it would be fine right?

[ebxjbob]

So your saying when you shift it from 4hi to 2wd the part time light doesn't turn off until you take a sharp enough turn?

[Menzenski]

do i have to immidiatly go to reverse to unlock the hubs
D30 hubs don't 'lock' or 'unlock'; they're always engaged. It sounds like you have a vacuum problem, if your axle doesn't disconnect when you put the t-case back in 2wd.

[90xj06]

in the book it states to drive back 10 ft. and when i do i can hear the axle un lock and then the light goes off.
and the front axle cant always be locked. i can freely turn the drive shaft with it in park and the wheels on the ground.

[RichP]

Your 90 has a disco axle, it's vacum controlled, it has a vac motor on the passenger side. When you put it from 4 to 2 the transfer case releases the disco on the front axle. Alot here remove the disco and permanently attach the fork thats in there and an aftermarket company actually makes a mechanical conversion, forget the name off hand. Some here also put a newer D30 in the front that does not have the disco.

[90xj06]

well its not a problem but would it be fine to drive in 2wd with the light on? every thing if functioning like it should.

[Menzenski]

and the front axle cant always be locked. i can freely turn the drive shaft with it in park and the wheels on the ground.
The front hubs are always 'engaged'. Whenever one of your front wheels rotates, that axleshaft rotates as well. The reason you can rotate the driveshaft by hand is that your 90 has a vacuum-disconnect front axle. In an open differential, turning the driveshaft will make the axle with the least traction (read: resistance) spin. That axle (the one with the least resistance) is the passenger-side intermediate shaft, which is disconnected from the outer shaft and wheel on that side by the vacuum motor. If you shift into four wheel drive, your passenger-side axleshafts will be locked together and you won't be able to turn the driveshaft by hand.

[4xBob]

well its not a problem but would it be fine to drive in 2wd with the light on? every thing if functioning like it should.

Yes- no problem. With the transfer case in 2wd, there is no power going to the front axle. If the vacuum disconnect fails to disconnect, then you just have an axle like the 1991-up D30, which has no disconnect.

[90xj06]

ok thank you thats what i thought.
just changed my oil in it to 100% lucas oil.
my drive shaft is rubbing some where i got to find it.

[xjtrailrider]

If it does it again just slide under the Jeep and disconnect the vacuum harness from the actuater, and then reconnect. My 90' does this from time to time. I plan on getting one of the posi-lock manuel actuaters soon.

[davehoose]

i had this problem with my 89 xj aw4. changed the fluid (dex II) in the transfer case and it worked fine with the lights going part or full time. just a thought