Ask to see the fluid that was in the pan, you would be able to see the clutch material in the fluid. Most important of all, if you do need a rebuild then get a rebuilt one from the local dealer. MB rebuilt trans come with 4 year 50,000 warranty. The job pays 5 hours labor and the MB tranny should cost no more than $1750, also if your creative you can ask the parts guy at the dealer to give you a break on the price and maybe sell at the wholesale price wich is list less 20%. As for your tranny, to do a front pump reseal you take the pump out with the trans inverted(tailshaft down) nothing else comes out of the trans. So trans R&R is 5 hours and the pump pays 2 hours, total labor should not exceed 8 hours.