Maybe i should title this going nowhere on a snowy day

My question is; how does the transfer case transfer power between the front and rear axles. Is it basically an open differential? I ask because that is what mine is acting like.

I'm trying to drive up my somewhat steep, snow covered driveway and as soon as one rear tire slips I'm going nowhere. I understand that i can't expect too much from the rear as the truck still has an open diff in the rear. But shouldn't the pig put some amount of power to the front axle regardless of what the rear is doing? I would expect to at least spin one tire on each end but it aint happening.

Does the xfer case have to see traction at the rear in order to put any power to the front? Do i have to have a limited slip/locker in the rear before I can expect to see any torque passed the the front axle?

 

Your intuition is correct. You should be getting some spinning on the front end also. Are you engaging 4x4 out on the street so that you know your front end is locked in before you hit the steep stuff?

 

NO, its usually a last minute thing to avoid abusing the system on the (plowed) street as I turn into the (unplowed) driveway.

What kind of distance are we talking to get the system engaged?

So, in theory, if I removed the rear drive shaft I would be able to drive the truck if I was in 4HI/LO?

 

Yes, in 4H or 4L you should have power to the front axle.

Unless you have your foot to the pedal (spinning the rear wheels) your front end should engage nearly immediately and quietlly. If you are spinning your rear wheels, you should hear a sound that makes you a little sick to your stomach (a bit of grinding from up front).

There are some other discussons on this forum where owners talke about needing to slap their stick to the left (toward the neutral drop down) in order to get 2H to engage; as well as some discussion of diagnostics by smarter guys than me. I jumped 15 years with my most recent purchase, so don't have much experience with some of this pepsi generation technology I'm riding around on.

Sounds like you've got a problem tho, and hopefully it's electrical and not in the front axle.

 

If you have the electric TC shift, the shift motor may have stopped working.

Ian

 

My old 91 Explorer had a simlar problem, and it was the shift motor. If it gets out of alignment by even a hair, it will not shift into 4WD.

 

To answer your original question, no. The transfer case in the F-series doesn't have a differential in it. It's 1:1 and locked. There is no slippage between front and rear axles.

There are a couple things you need to look at.

There's a possibility that the transfer case isn't engaged. It's probably a control problem. If you have the floor shift, then it's probably the linkage. If you got the electronic shift, it's probably the motor that's stuck.

The second thing you need to look at is if the vacuum motor on the front axle is engaged. If it doesn't engage, you'll have power to the front drive shaft, but the front axle won't get any power since it's an open differential.

BTW, if you're only using your 4-wheel drive for driving in the snow, you're not using it enough. You should get your truck off the street and onto dirt and engage the 4x4 once a month to keep things working right. I hesitate to suggest this, but you can also engage it on paved roads, but do it in a parking lot keep your vehicle going stright. Avoid making turns.