evmo

Tried to search...nothing.

I just noticed today when my girlfriend moved my jeep that the front drive shaft is turning when 4 wheel drive isn't engaged. The jeep drives just as it would in 2 wheel drive and seems to be locking into 4 including 4 low just fine.

Upon inspecting it I found a small hose coming off the top rear left side of the front differential that seems to be damaged. Is this the vacuum disconnect? If it's damaged is this the symptom it would cause?

winston427

You do not have the vac disco front axle on your 00 model XJ. The hose you are most likely looking at is the vent tube for the front axle. It should be routed up the firewall and secured with a zip tie near the brake booster with a small check valve on the end.

nasonguy

what transfer case did you have?

IIRC...

NP242 (part time/full time 4wd with 4lo) didn't have a vaccum disco...

NP231 (4hi 4lo part time only) did have it...

SeriousOffroad

Nope, you don't "RC."
The OP has a 2000 XJ, no vacuum disconnect regardless of the t-case.

97XJMopar

Mine has a NP231J t-case and my front drive shaft turns when in 2wd. Always thought that was normal for Jeeps where they didnt have locking style hubs

evmo

I have the NP242 (part time/full time 4wd with 4lo).

SeriousOffroad

Winner Winner, Chicken Dinner!!
It is perfectly normal.

mobilecherokee4

yeah mine does it, they all do i think, i had to take mine out cause it broke and icouldnt drive it without it making an awful knocking noise

mobilecherokee4

but i have the NP 231

evmo

Really!? Well that's good. Funny though I've had this thing since 2002 and never noticed it before. Then again I'm usually driving it.

zjrog

The driveshaft will turn unless you have manula locking hubs, or a vacuum disconnect, and even with the disco, it still CAN turn...

nasonguy

Haha, ok.

the '98 models did though, right?

I remember seeing something about it in my chiltons when I was reading up on dropping the axle (that was fun...), but now I am skeptical of my memory, I don't even remember seeing a year range.

evmo

I lifted it 3" about 2 months ago and this was the first time since then that I watched someone else drive it. I'm guessing that's why I never noticed before, the front shaft wasn't obviously visible at stock height.

SeriousOffroad

No.

winston427

91 was the last year that had the vac disco front axle.