My transfer case is the NV242HD. It has 2WD, Part Time 4WD, Full Time 4WD, Neutral, and 4-Low. Two questions:

1) Can I leave it in Full-Time 4WD all winter, even on the freeway too? My truck is tricky to take in and out of 4WD, so if it can't hurt anything I would rather leave it Full-Time 4WD until the snow disappears in March. Most driving will be on wet/dry pavement, but when it snows it will be heavy for a few days, then back to pavement when the snow melts. On and off all winter.

2) Will my gas mileage suffer if I leave it in Full-Time 4WD? My assumption was Full-Time 4WD is actually 2WD until a wheel slips, then it locks in 4WD. So I assume gas mileage wont suffer since most of the time my wheels wont be slipping.

Thanks guys!

 

Don't quote me on this but I am fairly sure that you do not want to drive more than 35-40 mph in 4wd. Also not on firm surfaces.

 

Thats what ive always been told, no more then 45mph, but id wait for a more reliable source to answer your question.

 

for part time 4wd what has been said above is correct, the full time 4wd option offered on your t-case is similar in practice to AWD in that you can leave it in at all times on dry pavement/wet pavement/snow and it shouldn't hurt anything to leave it there at highway speeds. however your gas mileage WILL suffer doing this since you are splitting power btwn the front and rear axles and you are making the engine DIRECTLY turn more mass (yes the whole driveline turns in 2wd too, but in 4wd there is a connection btwn the engine and the front driveline, in 2wd the front is turned by the front wheels),

 

NO, you should not drive in 4HI all the time. You can ware out the Viscous Coupler and blow the T-case.

Yes your gas mileage will suffer.

Your assumption is incorrect. Don't do it! Torque can move between front and rear, but it usually moves more to the slip point than the grip, however it will also move through the Viscous Coupler. This is not something that should be used all the time. You are going to have to get used to only locking in the 4X4 when you NEED it and not when it's just a little slick.

 

Thanks so much for both your inputs, but I am getting two different answers... anyone may be able to explain which answer is best, in detail. It would be really nice to leave it in Full-Time 4WD, but I do not want to do it if it is going to wear anything out. Thanks again, you both are a big help around here.

 

notti, Just my 2 cents, I would not leave it in 4 wd all winter. Bad for mpg's, bad for drivetrain, bad for truck in general. The switch in right in right in front of you so just switch it in and out of 4wd when you need it, otherwise always leave it 2wd. A flip of the 4wd switch is a whole lot cheaper than replacing a transfer case or a transmission, even if it takes a minute or two to get it to shift the t-case. I would rather take the extra time than chance busting something in the driveline.

 

im not going to lie, im not 100% familiar with your transfer case, hydra owned a truck which had the case in it iirc, so trust him on it, all our trucks have had part time 4wd 2wd and 4 lo so i went w/ my gut and was apparently wrong

 

Our Ds were made for 2wd primarily. That's why we have the switch in the cabin. Personally, I would not leave it in 4wd hi all the time. Like duram and others have said, just use the switch when you need 4wd. Just my .02.

 

I use mainly 2WD. If I start slipping in that I throw it in 4 WD PT, If I need better traction than that I throw it in 4 WD FT pulling over each time putting the drive in Neutral to pop it in the four wheel drives. If there is snow/ice really bad on the road I just slap it in 4 WD FT and go on for the day then when I am done running around paying bills or shopping I put it back into 2 WD. I think this is the same that Hydra said to do as well more less.