I never had problem until new rear differicial installed 3 months ago. When street is wet it is bad if I go over a bump or a railroad pass in the road. The rear will seem to slid to right then left.
my car shimming when I go on rough spots in road, especially wet streets, why? on 2005 Volvo XC70
If it only has happened since rear end work was done I would have the rear suspension blots and bushings rechecked to see if anything is loose or worn, check the condition of the tires and tire pressures.