the reverse idler gear in the tailhousing got taken out and mixed up during disassembly and not sure how it goes back in. My service manual isn't very specific it just says don't take it out unless it is damaged. one side has 2 machined grooves in it and the other has only one. Any info would be a great help. thank you.

 

the diagram I have looks like the machined face on the gear is offset, when it fits in there properly the gear teeth will be closer to the back of the transmission. If you turn it around wrong, the gear teeth will be closer to the front of the transmission and won't mesh with the reverse gear. But it is hard to tell from what I have, if you're still struggling next month, I'll post up when I open up my T-56 and see which way it fits.