47 RE gas and diesel differences. This is mostly from memory so forgive me if I forget something.
Main differences:
*Front drum capacity. Usually only 3 fwd frictions. Diesel is 4 and it has to do with the position where the snap ring groove in machined in the drum. It sits lower in the drum itself. I have found some gas version to have a 4 clutch direct drum but it may be from previous rebuild.
*Front planet is 4 pinion and not 5. Diesel is 5 pinion steel.
*Rear planet may be 3 pinion instead of 4. In diesel application, the rear planet was 4 pinion aluminum.
*Overdrive brake clutch capacity is usually 4 clutches vs 5 on the diesel. Pressure plates can be changed.
*Overdrive Direct clutch count is usually 8 clutches with thicker steels and pressure plates to make up for the difference versus the 10 clutch in the diesel
* Valve Body has differences but it is usually the separator plate, shift control timing springs which include 1-2, 2-3 shifts, and TV spring from what I can recall. Now, the 48re valve body does have more than a few differences vs the 47re. Here I would stick to a diesel application.
*Other small differences band lever ratio, accumulator with 2 spring instead of one.
*As far as the shafts are concerned. They all interchange. I can not tell you if there are differences in the orifice sizes although I do not believe there is. Maybe someone else can chime in on this.
This is pretty much a complete list but remember, Gas 47re vary based on what was their application. I have seen and worked on more than one type of 47re gas transmission.