My TOD is acting funny. Only getting rear wheel drive. Driving in snow, the front wheel indicator does not light up. I don't have any TOD check light or check engine light on. When I put it in 4-lo, it moves a little better in the snow, but still spinning the rear tires. All 4 tires are the same size and brand. Change transfer case oil, but no improvement. Any help is appreciated.

Thanks.