the ride height in the wagon is determined by the valve setting on the level sensing valve that feeds hydraulic fluid to the accumulators and the shocks.
DO NOT try adjusting this unless the car is on jack stands, as the car will drop down suddenly if you activate the valve manually. There is a control arm that attaches to the valve itself, sometimes the connecting link breaks and a wagon will take a low attitude and not level itself. If in doubt take the car to a mechanic with experience because excessive tire wear can result if the valve is set wrong, causeing excessive camber and the car will not handle properly either.

I haven't seen a diff mount fail, but it could happen. I think it would start clunking and be a dead giveaway if it did bust the rubber loose.

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!