If this only happens at night I would take a look at the viscosity control. Dover heats the oil by running the pump motor and bypassing the oil thru the valve. I would block calls and force the car on to viscosity control and see if you hold floor level.I would also try the manual lowering as suggested by solidstate and if that checks out fine do a standing load test and see if oil is coming back thru the valve and determine why LU is not keeping you floor level. GOOD LUCK
