Here is an interesting bit related to the clutch pilot bearing and crankshaft for 37-39 cars/trucks... Receiving the clutch aligning tool and new Hyatt bearing (GM 142655) helped me clear things up; it seems that I was mistaken about my statement before affirming that the 3 speed transmissions use a smaller pilot bearing or bushing.. Incorrect. As it turns out the clutch tool fits inside both the Hyatt style bearing, GM 142655 and the ND 7109 or GM 907109..
So, the only difference seems to be that GM 907109 pilot bearing is paired to crankshaft GM 838345 for the year 1939, but I don't really know which crankshaft corresponds to the Hyatt style pilot bearing 142655... Even though my truck is a 1939 model, NOT equipped with GM 907109 bearing, but with the Hyatt pilot bearing in the crankshaft... How can that be?
Furthermore, to make things more confusing the book has a note, for pilot bushing GM 412562, All 1939-1951 (Except P.G.) "When installing this bushing on jobs equipped w/ Hyatt bearing 142655, omit 473681 stop spring...
By stop spring do they mean what appears to be a small plate/washer that fits against the Hyatt bearing? Last two photos...
