I picked up a '93 XJ as a bad weather dd. This is my first Jeep and I don't have an owner's manual and I think my question goes deeper than the manual would cover anyway.

When I engage 4wd a light comes on the dash that says 'Part Time'. What does 'Part Time' mean? At parking lot speeds on dry pavement (when I would expect 'part time' to mean not active) it stutters and bucks as if 4wd is fully engaged. No, I don't use 4wd in the dry, I was just experimenting.

Is the front diff a limited slip? I guess this could loosley qualify as part time. Is there some kind of sensor in the transfer case? If there is I don't think its working. What do the experienced Jeep guys saw about this system? How does it work, is it durable, when it breaks what breaks most often?

I'm not worried as the 4wd works when I engage it and it goes where I point it. Just curious.

Thanks,
Rev.LowBuck

 

I'm assuming you have the command-trac system. The command-trac is meant for "part time" use, meaning only in loose soil/mud ect . Jeep actually explains it pretty well on the site. The binding they talk about feels like the jeep is bucking. http://www.jeep.com/en/4x4/how_syste.../command_trac/

 

What are the positions on your transfer case?
Im gonna guess:

2wd
4HI
N
4Lo

IF thats the case then you have the NP (New Process Gear) 231 Transfer case.. this is a PART TIME ONLY transfer case..meaning you can not use 4wd on the dry pavement at any time..only for "part-time" use.. meaning offroad applications.

If your shift lever has:
2wd
4HI (part Time)
4 Full Time
N
4LO

Then you have the NP242 transfer case.. you can use the full time option on it for normal street driving.

Unless someone added a LSD to your front then no...its an open differential.

 

Here's a recent conversation about full and part time 4x4...

https://www.cherokeeforum.com/f2/par...-light-158545/

There are others, just gotta search around a little. If you don't have the 4 full-time detent then you've got an NP231 transfer case and you can't use 4x4 on dry pavement without causing fairly immediate damage.

 

Part time is what I think most consider "standard 4WD" where the front will buck when turning on dry pavement. Full Time is what most consider AWD, where the driveshafts are not locked with each other, but rather rotate at different ratios to eliminate normal 4WD issues on dry pavement. Im sure someone will chime in with a more technical answer.

 

 

Aahhhhhh!
So the "Part Time" idiot light means "Do NOT engage 4wd FULL TIME, you idiot"

Got it
Didn't look at the back of my visor...I'm gonna feel dumb if I have one of those labels.

Thanks All

 

Nope... The Part Time light means Part Time is engaged lol. If you're on dry pavement you should switch to Full Time

 

Haha.. That's funny

 

The part time idiot light is for the full time idiots that don't read the label on the back of the visor.
Went out and checked, sure enough it was there in plain English.
My excuse- I live in southeast MI where we don't use visors because we have the 2nd least amount of direct sunlight in the US.