by Todd Hill, VolksWerks Transaxles, Olympia, WA
"Is there any way to identify the year of manufacture of
a type II transmission by external case stampings or any
other external method?"
What year Bus we talking about?
The '68s were a one year only style maincase in which both of the side covers under the inner CV flanges were held on by studs and acorn nuts rather than the later screw in style retainers.
1969-1974 pretty much look the same except that the '71-'74s use the later style T/O bearing and clutch arm.
The 1975s are also a one year only 002 maincase with 5 larger ribs vs. the 3 ribbed earlier cases. Also, AFAIK, starting in 1975 the last digit of the serial number reflects the year in which it was made. But since it is the 5 rib version you'll know its a '75 simply by looking at it.
the transaxles are the same with some minor modifications
changes in gear ratios, and ring and pinion sets.