Hi folks,

Little confused so perhaps someone can enlighten me.

Have a 96 XJ auto which has the 2wd/4wd option

When it's in 4wd I get a green dash light/diagram that appears to show both front & back axles working. However when I change this to low range the green light disappears and I get a "part time" light instead.

Is that right? Seems the wrong way around to me

 

What transfer case do you have? On the shifter bezel is there a part-time and full-time 4wd?

 

Part time means part time use, like off roading. Since you shouldn't be driving around in low, that light comes on. I've got a 242 and I've got full and part time lights. If you have 4 hi and 4 low then you've got a 231 transfer case.

 

yes it has both the part time & full time options in 4WD

To me part time implies it engages in & out of 4WD when it see's fit, where as full time stays locked in 4WD "full time"

Sounds like that is actually the other way round huh?

 

in full time 4wd the drive shafts are not locked together making it ideal for driving around in 4wd in the rain or snow. part time locks the drive shafts together, more suited for rocks or hills.

 

Part time means you can use it part time. Full time means you can use it full time on all road surfaces.

 

Full time uses a series of clutches in the T case so that nothing will bind up and break on pavement. Part time is true 4 wheel drive and can only be used in conditions that will allow the wheels to slip. It is more "locked in" than the full time option

 

Actually there are no clutches. It's an open diferential and it will allow all the power to go to one wheel in poor traction situations..

 

That's because 4WDLO is a "Part Time" range, since the differential in the transfer case is locked front-to-rear (typically 52/48 torque split, front bias. Sometimes 50/50, but the front bias is usually done for vehicle control.)

Run in 4LO on good surfaces long enough, you'll blow up the transfer case.

If you have the NP242, you'll have a "Full Time" mode as well, your shifter should be labelled "2WD-4FT-4HI-N-4LO," or something similar. With the NP231, you simply eliminate the 4FT mode (the shiftgate is modified already.)

The NP242 was used in higher-end XJs (Limited and Laredo trim, usually,) with the 6-242 and AW4 four-speed automatic. The NP231 was used in pretty much all the rest (although 1984-1986, as I recall, can get a little odd.)