Cusser
+1y
Gear oil can be added to the manual gearbox by removing the fill plug on the transmission side, and pumping some in (pump screws onto gear oil bottle). Some add from the top after tearing or removing the top boots, I know if I did that I'd get gear oil allover the interior.
I'd check/add gear oil to the differential while I had the stuff out.
On my '88 B2200 (mine since 1994), when starting off cold, I frequently find I have to move the gearshift mostly into reverse, then as I slowly let out the clutch a hair, I slide it into reverse fully. After I'm in the street, with foot down on clutch pedal, I move through forward gears 1 & 2 then put into 1st and drive away.