Will do. If a pump went tits up that would explain everything. Where are they located inside this transmissions?

One pump is at the front but it has a rear pump also I think. I believe a failed front pump can sometimes be overcome by a functioning rear pump. Is that right?

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Drained the fluid and put a new filter in. The inside was squeaky clean as was the filter, pan, and fluid. After that it didn't want to move but after a while of shifting the selector between reverse and drive it started engaging, then driving. Today I started the car after sitting for two days and the transmission worked great.

There's a whirring noise when in park or neutral that goes away in reverse or drive. In drive it's quiet, shift in to reverse and there's the whirring noise that goes away as it engages reverse. Then reverse is quiet, shift in to drive and there's the whirring noise that goes away as it engages drive. Put it in park and the whirring starts back up again. Sounds like a whirring mechanical actuator.

Been looking in to the B2 piston thing, seems likely but at the same time not really.

Hi Kingman, did you ever sort this out? I'm having a similar problem now with my '79 300TD...

Hey there. I didn't exactly get it "sorted out" per se but the fluid and filter change seemed to have cured the problem, along with moving a transmission vacuum line so it actually sees proper vacuum - it no longer slams through the gears and engages drive/reverse quickly and consistently.