My '57 2 ton now has a vacuum shift 2 speed rear differential. The truck was originally a single speed but through the grace of one of our big bolt members I was able to purchase from him the parts needed to convert. The shift valve on mine was in pretty good shape internally, I disassembled it, cleaned and lightly lubed with silicone based lube so as not to destroy the rubber. I did replace the shift diaphragm in the differential actuator. When shifting on the road, I can't hear the air movement through the vacuum system, if the truck is sitting still with the engine not running, I can shift it and hear a little air through the exhaust filter. I added a vacuum reservoir so I do have the ability to shift it a couple of times with the engine not running.
Last edited by 78buckshot; 09/22/2024 9:42 AM.
