Unimog Club UK

The dampers won't make a difference to spring rates just control of the springs. The sump on a OM 636 has a front mount sump that sits over the differential if your going to put a snow plugs on the front you need the heavy front springs ( I have some in stock ) they are very stiff with no load.
Regarding the sump all I can think is did they do that engine with a front mount sump or modify the one you have now.
Moose