I have a 1998 Dodge 2500 SLT Cummins 12 valve
had small fire in engine fuse box truck still runs and drives but only has first and reverse. What do I look at to be able to make a shift again? The PCM was out before this and I manually shifted it from 1st to 3rd and it was great around town, just trying to get this going for a few months as I am just out of the hospital and semi-disabled looking for help

 

I'd consider replacing the damaged wiring harnesses - you can go on car-part.com and find wrecking yard parts if you aren't physically able to go yard-crawling yourself. maybe look for someone nearby whose parting out a vehicle and will pull it/them for you.

My understanding of the 47RE (we have the same trans) is that the valve body is essentially a standard hydraulic valve body for gears 1-3, but line pressure is electronically regulated by the PCM. It's interesting to me that you can effectively use 1-3 even manually shifting - but perhaps the pressure solenoid goes to max if there is no PCM signal.

 

The strange thing is after the PCM went out and I manually shifted one to three fuel mileage around town jumped up. I'm shifting by ear about 1600 RPM gets about 17 mph around town go figure

 

I'm guessing your torque converter is slipping a lot less thus making it more efficient. Are you saying it will not shift out of first after the fire?

 

Shifting problems solved
Replace blown fuses bypass fuse box with new 140 amp fuse to battery fix that problem. Now I have another bad alternator. This will be the third. This one is making noise after I repair the wiring.