I have a Mid 80's Kubota B6200E and that deck is a dead ringer for the MMM it came with from the factory. As people have said, the gearbox is not the factory unit.
So are you saying my MMM will only fit on a B6200? Mine came from the dealer with it and I want to migrate to a rear mower. Do you think I can sell it? Unlikely if it only fits the 6200.
Tom
Kubota L3830GST, B7500HST, BX2660. Formerly: Case 480F LL, David Brown 880UE
Stick it on Craigslist and see if anyone is interested in it. There is probbaly someone else out there looking for it. When Dad sold his Deere 755 TLB, it went 3 ways. One guy bought the backhoe, and a couple of brothers bought the tractor/loader as one bother wanted the loader and the other wanted a mowing tractor...