[rotorwrench]

Folks have made tube baffles to fit inside the torque tube but they are to keep the rear axle lube from going forward when folks install dropped axles and not so much for reverse flow. Oil from the U-joint housing is generally not a major problem but like anything, problems can creep in for one reason or another. That shaft damper bearing would likely not like a lot of oil going back there. The rubber donut around the bearing would act as a dam and get soft if bathed in oil all the time.

The slinger ring or baffle on the rear of the main shaft just in front of the rear main shaft carrier bearing will usually keep most of the oil in there unless it gets overfilled. A person can put a sealed bearing in there but I've never had any problems with a seal on just the aft side of the bearing. I like gear lube to get to those bearings. Grease won't last as long as bath oiling will. Most greases have a shelf life of around 4-years. On the helicopters, we pull the seals and regrease them every 24-months but they are a lot easier to get to than the main shaft bearings are in an old Ford.