Had a similar problem but not on a Volvo.Traction switch was buggerd so was feeding lift axle suspension bags low pressure all the time to give drive axle a bit more bite. Replaced switch and pressure evened out.
Had a similar problem but not on a Volvo.Traction switch was buggerd so was feeding lift axle suspension bags low pressure all the time to give drive axle a bit more bite. Replaced switch and pressure evened out.