Rear wheels spinning in 4wd low?

[Chris Petrini]

Hi there I have a 2017 2500hd with the 6.6l v8 4wd. Yesterday I encountered something I thought was odd. I was pulling a stump out of the ground in 4 wheel low. And my rear tires were losing traction (expected) and essentially burning out. I would expect in 4wheel low, for the front tires to pull me forward but they didn’t. It was as though all the power was going to the rear wheels. 
 

As far as I know the 4wd shift was successful, the 4wd light was solid and tc and abs shut off automatically. Isn’t the whole point of 4wd low to have all 4 wheels spinning, especially on a truck with an automatic locking rear dif? I mean I was literally doing a burnout with my rear wheels in 4wd low. Doesn’t seem right.

[davester]

Well, there's no locker in the front diff, so at best you only get 3wd (so, you could spin both rears and one front wheel).

 

A simple test if 4wd is working is to:

-put the truck in 4wd (say, 4lo) and move it a little, to make sure the various gears engage in the transfer case and front diff.

-lift up one of the front wheels

 

If you can't spin the front wheel, then 4wd is engaged and working.

 

If you can spin the front wheel, 4wd isn't engaged for whatever reason.

[Chris Petrini]

12 minutes ago, davester said:

Well, there's no locker in the front diff, so at best you only get 3wd (so, you could spin both rears and one front wheel).

 

A simple test if 4wd is working is to:

-put the truck in 4wd (say, 4lo) and move it a little, to make sure the various gears engage in the transfer case and front diff.

-lift up one of the front wheels

 

If you can't spin the front wheel, then 4wd is engaged and working.

 

If you can spin the front wheel, 4wd isn't engaged for whatever reason.

Okay that’s a good tip, I’ll give that a whirl