Not all Wickham rail cars are created equal.
The gear box is back in pieces and now the front axle has to come back out and have all the shiny new paint damaged. The axle bearings need to be removed to replace a crown wheel for the forward gear.
Over the vehicles life in the type 4 Wickhams had design changes with the gearbox, only slight ones, but enough to to make parts incompatible. In my case the pinion gear does not mesh with one of the crown wheels in the gearbox. The crown wheels gears are a tad deeper than the other one. This caused the axle to bind when the gearbox was tightened up on the axle.
I'm now back to where I was 2 weeks ago. Yippee!