Triumph Repair: Spitfire transmission, flange bolt, bronze bushings

Question
Recently I was descending a steep route and my transmission popped out of 2nd gear.  It has been popping out since.  What happened?
Also, what is the difference between the early and late MKIV transmissions?

Answer
Wes,

The gears ride on the mainshaft on bronze bushings and are "locked" into gear with spring loaded ball bearings in the synchro hubs.  Once there's enough wear in the bushing or the sometimes the syncho then on overrun the trans will pop out of gear.  

As to the gear boxes, the only difference listed between the Mk IV gearboxes is that the early units (up to FM60000) were fitted with a D-type o/d unit and the later gearboxes were fitted with a J-type o/d unit.

The Mk IV gearboxes were different from the Mk I-3 in that they are synchronized on all 4 gears and have a larger output flange bolt circle.  Perhaps that is what you're quetioning?


Cheers,

Jim