Things ya have to do when ya custom build things for extreme use...TA driven gear in this custom built ass. is a lot wider than an oem gear, assembled everything and noticed a slight drag, after inspection we had to remove everything & clearance the housing for extra wide gear...
...ended up with just enough clearance so nothing rubs. Used a new LH threaded HD thick walled countershaft, and all new roller and needle bearings.
...we did run into more oem junk...splined countershaft spacer ate its pigs after tightening shaft to 450 ft. lbs & brand new bearing was a few thousandths out of round and would stop itself rolling around in your hand and wouldn't go onto shaft...always something.