1938 Banjo Rear Temperature

mramc1

mramc1

Member
I have a 1938 4.11 banjo rear in my Model A coupe. I don't know if I have a problem our not, but the "banjo" center section gets pretty hot after driving the car. I have fresh 600W oil in it up the fill plug. When I jack the rearend up and spin the wheels and drive shaft (I have an open yoke conversion) there is no looseness, noise, or binding in the axles or the driveshaft. I'm running knobby rear tires so it's hard to hear if there is any whine when driving the car.

I know rearends gets warm when in use in any car, but this one gets hot to the point you don't want to leave your hand on the pinion which seems too hot to me. The axle bells are cold at the wheels and away from the banjo. Do I have a failing inner pinion bearing? I put a new outer bearing in because it was accessible. The old one appeared okay, but I changed it anyway and no difference in the temperature.

Any insight would be appreciated.
 
If you are using true "600W" oil that could be part of the problem, 600W is steam cylinder oil with it's listed uses as steam, and worm gears----then there is the 600 series of gear lubricants that the listed use is spur and bevel gears---like Shell Omala 680---this is probably too thick for the later axle you are using, try using 90/140 weight gl1 gear oil ---or you could have the preload set too high on the bearing you replaces
 
Kurt in NJ said:
If you are using true "600W" oil that could be part of the problem, 600W is steam cylinder oil with it's listed uses as steam, and worm gears----then there is the 600 series of gear lubricants that the listed use is spur and bevel gears---like Shell Omala 680---this is probably too thick for the later axle you are using, try using 90/140 weight gl1 gear oil ---or you could have the preload set too high on the bearing you replaces
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I'm using 600W oil that Mac's sells. The pinion preload isn't very tight, it was actually a little loose and the pinion was moving in and out a few thousandths. I adjusted it to just a little past snug so the pinion wasn't moving. The manual has a strange preload setting, I think it's torque setting spinning the gear set with the rearend fully assembled. Either way I seems like the preload is a very low torque setting.
 
Easiest thing to try is to run a light weight gear lube or like Kurt suggested a multi grade lube. Not sure why he suggested GL1, I would run GL4, or even GL5 for that matter, there is no "yellow" metal in the rear axle.
 
I use Lucas heavy duty 85-140. It is a clinging oil. As for heat, the only time I had heat in a banjo I was running tight used bearings at high end of torque setiing.
I loosened them to a light drag and they have been fine.

John
 
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