I had problems with my 4 Wheel drive in the recent snow, I was skidding and not able to go up small hills as the wheels skidded. I thought it was the tyres as they were cheap ones I got for the MOT. I have since bought goodrich ones but Sat I got stuck in mud. I think the front wheels are not engaging. The 4 wheel light comes on but it seems the ffont wheels are not moving. Any suggestions?