Ed,

This is a restored '36 PU so keeping it original is a priority. It does have a torque tube. I have made some significant alterations like this:

http://vcca.org/forum/ubbthreads.php/topics/334876/1936_Chevy_3.55_rear_gear_conv

but they are visually undetectable.

If the present gear oil experiment doesn't solve the 3rd gear engagement problem I'll accept that the '32-'36 3-speed synchronizer design simply can't do any better. It's probably a design conceived in the late 1920s, nearly 90 years ago. That is part of enjoying any antique vehicle.

Synchronizing 3rd gear requires speeding up or slowing down not only the input shaft ("main drive gear") but also the countershaft gear ("cluster gear") and the reverse idler that are both always in mesh with the input shaft. The latter 2 gears are always below the oil line so the more viscous oil should at least help slow them down for the 2-3 shift. Time will tell.

I appreciate your interest.

Ray