I installed a 4sp OD in my '37 using one of the aok adapter plates. Very few modifications, but it worked like a charm otherwise! Now I'm without my emergency brake though. I had a thought that if I could remove the drum from my 3 speed and mount it at the rear axle I could rig up a mount for the brake shoe band and be back in business.
I got as far as removing the rear pinion seal as the collar on the drum where the seal mates is smaller than the one on the original rear flange that I removed. I think if I can get the right oil seal in place I can figure out the rest. I believe the seal actually holds in the bearing too, so I am a little concerned that the one I get from the parts store will not be robust enough. Has anyone successfully made this modification? Any help would be appreciated.