A week or so ago, I asked a question about a Spit transmission popping
out of 1st gear. I think the problem is solved, and I uncovered a couple
of interesting (and puzzling) items while doing the rebuild.
The Spit Mk3 parts manual lists 2 pocket bearings used during the
production run of the Mk3, but gives no change-over commission numbers. I
had three gear boxes apart while doing the rebuild and found that 2 had a
small, totally enclosed pocket bearing, and one had a larger, open-cage
type bearing. I don't know if the larger bearing is the same as the one
used in the single rail transmissons as I didn't have one in hand to
compare. TRF was able to supply a new bearing using the later part number
in the Mk3 Parts Manual.
Interestingly, the mainshafts that had been riding in the enclosed type
bearings showed noticable wear while the mainshaft riding in the bigger,
open bearing did not. BTW, the open bearing used a different input
shaft, which also had 2 part numbers in the Mk3 Parts Manual.
I don't know the source of the transmission with the bigger pocket
bearing. My car is a 1970 Mk3, the last of the Mk3s, and the transmission
I pulled from it had the smaller enclosed bearing. I don't know if this
transmission is the original unit - perhaps it was replaced by a PO with
an earlier unit. If it is the original unit, it makes me wonder when the
change in pocket bearing design actually occored. Perhaps the 'box with
the bigger pocket bearing is a MkIV 3-rail tranny? It was identical to
the Mk3 transmission in all other respects.
Waiting for the snow to melt so I can take it out for a shake-down cruise,