BTW, For a while I thought I had the perfect solution to an overdrive for a 1/2 Ton Chevy/GMC truck, especailly one with the low hump floor like mine has.
Someone was converting Muncie M-21 and M-22 4-Speeds to an OD trans. They were replacing 3rd Gear with a 1 to 1 Gear and 4th Gear was an OD Gear.
Perfect swap with no or just about no modifications on an original 3-Speed truck, again like mine.
Problem is, as it was explained to me, that many people driving in the city would keep it in the 3rd Gear position, which was not originally designed for long term driving and it was wearing out the bearings.
...Idea scrapped.
Wondering if the same bearing wear would happen still if converting a SM420 or SM465 over to an OD? My guess would be yes, but I'm wondering if it's ever been proven either way?
Bill
