I just noticed something and wanted to run it by the board. The A3 first gear doesn't appear to have a bushing pressed into it's center and the A35 first gear does.
Aside from the A35 have substantially larger straight cut gears, it looks like Tomos added a brass bushing to gear shaft surface.
That gear is supposed to slide over the shaft and allow the shaft to spin at full speed through it after second gear is engaged. I recently overheated an A3 and the gear is so tightly seized to the intermediate shaft that I can't beat it off with a sledge hammer. I don't want future failures, so I'm considering whether I should have a bushing installed at a machine shop down the road.
In this video you can see the gear being slide over the shaft with a little bit of shaft play. Unless I'm missing it, the A3 first gear has no bearing surface, so the contact surface is iron to steel.
Important part at 59 seconds: