so i know what 4x4 is, i know what AWD is, i know 4x2 is. but what the hell is "part time 4wd."

my friends dodge durango has it. does it only go into 4x4 when the back wheels slip? is it basically AWD? this is on a 1999 model or something, nothing really really new.

thank you
conor

Your Xterra has part time 4WD. That means it's a 2WD until you shift the transfer case into 4WD.

i dont think i was clear enough...

he has 2wd, then he shifts into "part time 4wd." on the dash, instead of any kind of 4wd, or 4x4 or symbol, it says "part time 4wd." then he can also go into 4x4lo...

Yup, that's exactly what I said. He has a knob or switch though, instead of a lever. The knob on the Xterra transfer case lever is just too small to print the words "Part Time".

sorry if im getting annoying...

but does that mean, when we shift into 4x4 and the hubs lock, and driveshaft is going, we are in part time?

does that basically imply that all four can have power and both diffs are getting the power, but some times less than 4 tires are actually driving?

thanks again... very helpful.

the '05 re-designed Xterra will have it printed on the knob.

Yes, when you shift into 4WD and the hubs lock, etc., you are then constantly in 4WD. It's a "part-time" system in the sense that it's only 4WD when you move the lever to 4WD.

Both diffs get power all the time in 4WD and all 4 wheels get power most of the time. The exception is if you lose traction at a wheel in 4WD due to the conditions you mey be driving in. If that happens, all the power to that end of the truck goes to the uselessly spinning wheel because of the open diffs and you will effectively lose all traction at that end of the truck. But the other end may still have traction.

Hope this helps.

Not to but heads with anyone but my impression of 4wd is this. In my brothers jeep manual it states there is a part-time 4wd option and a full-time 4wd option. The part time option is to be used offroad or on slippery pavement(never on dry pavement); whereas the full-time option allows the driver to drive the truck in 4wd on all types of pavement without any negative effects. The difference being in part-time the driveshafts are turning at the exact same speed and in full time their is a mechanism that allows the drive shafts to spin at two different speeds(an example being making a turn).

Maybe what Dodge means is AUTO 4X4, my friends 95 explore has that. There is a little dial that says 2HI 4AUTO (only engages when sliping) and 4LO, full time 4X4. Full time 4X4 is that some Jeeps have no transfer case. Hope that helps

Correct, and that third mechanism is nothing other than another differential, this time in the transfer case. This allows the front drive shaft and rear driveshaft to spin at different rates.

Full-Time 4WD is just another term for AWD, just like in a Subaru.

(Xterra Kid, all Jeeps have transfer cases).

thanx xoc, that clears up the unknown mechanism for me.
Roger

due to the fact that the full-time-4wd's center diff acts as a chain-reactor from the front and rear diffs? kind of how an awd's system is relying on one differential?

Learn something new everyday! What about the full time 4X4 Grand Cheeroke? When I think transfer case I think something you turn or move inside the vehical to engage disengae 4X4.

Think of the transfer case as a case which either transfers power in another direction, or transfers it at another ratio.