I work on a service truck for heavy equ., and I have been told by our purchasing clerk that we were going to use TO4-30 for all useage except the motors. I have always used hydr.46 for hydr. systems,to4-30 for transmission. and finals. Is this wise?

Yes, diferrent application better use different lubricant. Because of the tramission lube and hydraulic , there have different additive package. Hydraulic oil consist of Aw additive and AO.