So, the midwest was dumped with 10" of snow and I was out playing in it. My new XJ has the NP242 so I decided to test full time and part time 4wd...so in deep loose snow I can't tell the difference. I got new Yoko Geolander A/T's on it and they grip great in the snow, but both settings on the TC pulled great.

I guess my question is, should I feel a difference in deep snow? Should I use one over the other? As I'm thinking, the only real reason to use full-time is when the snow is patchy on the ground to let the clutch in the TC save my u-joints as I go between slippery terrain and pavement...thoughts?

 

green for the roads(full time), orange or yellow(depends on the fade you have lol) for real time (part time)when you need it..never on anything that wont let the wheels slip or it'll cost you a transfer case chain.

 

In snow, I'd use part-time.

 

What's all this part-time/full-time/real-time hogwash you speak of? It's always been my understanding (as a mechanic) that part-time 4wd refers to that of XJ's and similar vehicles that can be manually or electronically shifted into and out of 4wd, be it 4H or 4L.
Full-time 4wd refers to certain Grand Cherokee's and other vehicles that are always in 4wd and CANNOT be put in 2wd.
Real-time 4wd or AWD refers to vehicles where the 2wd and 4wd modes are computer controlled with no input from the driver.

 

XJs came with 2 different transfer cases

The np231 (np stands for new process gear) is a part time only case. It has 2 hi, 4hi part time and 4 lo part time.

The np242 case is a full time/part time case. It has all the options the 231 does with the addition of a 4x4 full time option..you could drive down the highway all day in 4wd full time with no issues if you have the 242 case.

 

Part time is just 4wd meant to be used part of the time in at low speeds low traction conditions. It mechanically locks the front and rear outputs of the tcase together

Full time (in the np242) allows you to run in 4wd at all speeds and conditions because of a section of the tcase the acts like an open diff.

Full time is absolutely terrible offroad though

 

My Cherokee XJ has the NP242 transfer case with both options. Both mechanically selected with the TC shift lever. Full time has a 'clutch' that splits power transfer front to rear as needed, part time splits power equally regardless.

Sorry for the seemingly redundant reply in case I missed your application of the sarcastic font...

 

No clutch in full time. Just an open diff. Sends power to the diff with the least traction.

 

NP-231 is a part time case. Can be driven in 4wd only part time. Like when the road surface is slippery enough to allow slippage between the front and rear diffs which are locked at the same input speed.
Full time means you can use the system full time, like when you go from snow to dry pavement and back again. You could leave it in full time ALWAYS. Only your fuel mielage would suffer. The full time cases also have a part time option for more severe wheeling.

Both transfer cases can be sifted from 2wd to 4 High, either part time or full time at any legal speed. I've done it at some very illegal speeds numerous times.

 

part-time 4wd should never be used on dry pavement. more for snow and offroad.

full-time i would use for heavy rain or other favorable conditions, especially on the highway.

and of course 4wd lo is part-time only and should never exceed 15 mph.

I have a grand cherokee that is 4wd all time and the option to engage 4wd lo. I would assume full time is the same as the all time feature. You can probably drive faster in full-time mode. while i think part-time is max 70mph. You can engage 4hi part-time on the drive up 55 mph.

 

^may be totally wrong lol

 

You're talking to yourself.. LOL.

Any legal speed.

 

So, in super slippery deep snow does part-time give me more traction than full time (theoretically)? Cause from my experimentation I could not tell a difference...

I figured part-time would pull harder in the deep snow but both part and full-time clawed through snow up to the axle equally...

 

Part time actually creates a "slip" between the fron and rear diffs. Use full time in the snow. Gone are the days when aMC/Jeep used a viscous coupling i their transfer cases. 1986 for the XJ and 1984 or 1985 for the eagle. You could push snow with an Eagle til it stalled. But, you never lost traction.

 

You would think so... I lose, maybe 1-1.5mpg in fulltime when the roads are clear of snow. If it's snowy my foot's to the floor so my mileage goes to ****