The other day I went to use my 4 HI since the roads were crap on with snow. I go to take off and at about 20 MPH the truck acts like it wants to pull me off the road toward the driver side. The 4 HI will work fine when I'm going extremely slow, it is acting up when I start to speed up. I figured that it was a hub not engaging but all the tires are getting power. I do have the auto locking hubs. I just can't think off the top of my head why it would work at lower speeds and not just stop working all together if something failed. Any help/advice would be really appreciated. Thanks