I've got a 57 Chevy 2-Ton with a two speed rear end. The way you shift the rear end is a splitter selector mounted on the gear shifter. A cable runs from this splitter selector to a splitter control valve mounted on top of the tranny. It has five hoses running to it. One small one, about 1/4 I.D. and four larger ones with about a 3/8 I.D. When the selector is in high I can hear a vacuum leak and it is affecting the engine performance and it even kills the engine every now and then. Are these splitter control valves still available or what is a good replacement?