Last weekend was playing in the snow, very slippery conditions even with the winter tyres. I noticed on booting it (deliberately trying break traction) that the back end was stepping out of line a little, same direction each time. Apart from tyre pressures (checked) and alignment (not checked) is there anything I can do without special kit to see whether the rear diff is distributing power evenly ?

I've not noticed anything different driving on dry/wet roads, just in ultra slippery conditions last weekend.

Any thoughts ?

WRX MY99 Wagon