Quote:
Originally Posted by BillT
That sounds like a Clark 5-Speed Trans. I had one in the '62 6500 and in my '67 7500. It liked it as I could go through 9 Gears and only have to downshift the Rear twice.
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Yes! I'm sure you are correct about them being a Clark. Dad took the Whole Darn Family sometimes, Mom rode Shotgun, my Sister and I traded between the sleeper bunk and sitting on the doghouse. The truck tended to jump out of 5th, and got "Tarp Strapped" into 5th so rolling hilly roads were driven like a roller coaster, just shifting the 2-speed.
Too bad GMC didn't Tocco harden the 478 & 637 crankshafts. International Harvester Tocco hardened crankshafts in the old Farmall H & M model farm tractors. Some just months away from 80 ( eighty ) years old are still running regularly with the original crankshaft. I've only ever seen ONE broken M crankshaft and heard of one other. Undersize main & rod bearings are NOT common in them.
Company I used to work for Nitrided lots of parts. Biggest advantage of Nitriding was the low temperature the process exposed the parts to, nitrided parts needed little if any finishing after nitriding. Depth of hardness was not real deep but deep enough. If crankshaft was reground nitriding would have to be redone.
Chrome plating crankshafts was common, but not used much anymore. On a stressed part like a crankshaft pealing the chrome off was a possibility. A plasma metal spray technique would be better, but enough heat is put into the crankshaft all the journals would have to be reground.