I almost hate to open this can of worms, but what gear oil are folks using in their transmissions?  My 3 speed 37 transmission calls for SAE 160.  When I rebuilt the car, I used what I use in everything else I have, 50% 80/90, and 50% Lucas oil.  I recently drained the transmission to remove the speedometer gear, which is another thread that I will close up later, and I collected only 1 pint.  According to the manual, this transmission should hold 2 pints, 1 1/2 pints in the gear case and 1/2 pint in the u-joint housing.  It has always leaked some from the input shaft, but I didn't think that much.  It's been probably 2,000 miles.  Is that normal?  The bearing retainer is correct, the the drain hole is clear, at least it was when I overhauled the transmission.  Is my oil too thick to drain fast enough, or is it too thin?  The options I have come up with are 600W oil like is used in Model A's, 140, or synthetic 85/140.  Looking for some wisdom here because Googling this subject is baffling.