[Ledslinger]

Pondering what controls the end play of the gears and spacer on the idler shaft, it is probably the bearing cones on each end. The stack height of the two gears plus the spacer is probably the same as bearing shoulder to bearing shoulder on the shaft. Maybe the shaft shoulders are a few thousands shorter than the stack height of the gears and spacer to put them in compression. If the bearing cones do compress the gears, it would be good to shim the spacer to ensure compression.

Hazy recollections from rebuilding my T221 over 40 years ago, but I don't remember if gears on idler shaft were a tight fit on splines or not. May have had to drive or press shaft into the gears during assembly. A tight fit on the shaft was probably built into the manufacturing, and no play of gears on shaft intended. It may have been a more durable unit if both gears and spacer were manufactured as an assembly.