I have a 2004 range rover and it seems to act like open differential front, rear, and center. I dont have any error lights either. From looking online I have read the traction control system should be applying brakes to prevent it from acting like and open differential? I put it up on a hoist and put it in drive, just at idle and you can hold a tire on either side no problem and the opposite side will just spin, and holding both rear tires will send all the power to the front. I don't see any traction control in this case. is it just not possible to test it in this way? Was pretty dissapointed in its deep snow performance last year and was wondering if something is wrong.