TR2/3/3A Dismantling Speedometer...getting the odometer pin past the case???

A friend of mine is taking his speedometer apart and has reached the point where he needs to withdraw the case from the internals. He says that he is unable to pull the case past the odometer shaft stub( main part of shaft is off) because the case jams on the threaded speedometer fitting. What is the trick to getting the case past the pin? Says his speedometer is from a 57 and may be different from the later ones.

I used a small screwdriver to push the shaft into the case against the spring, like resetting the trip meter. Then some finger pressure against the threaded connection, so the threads don't drag against the side if the hole.

Kind of like explaining how to tie your shoe....The trip meter reset shaft will retract far enough past the case
to allow extraction of the internals. It (the shaft) is being stubborn because you need to twist the shaft as well
as pushing it to get it to fully retract. Under normal circumstance you do that automatically in order to zero out
the trip meter. It is a true PITA to do it with the stub removed. You can jiggle it & coax it & when it does fully
retract, slip a thin shim (.005) in the inside of the case to cover the hole & keep the shaft retracted.
I suggest doing that before you even remove the 2 machine screws holding the internals to the case.
The easiest way to accomplish this task is send it to a reputable speedo shop because after you get it
apart they will be able to solve any further problems.