Second gear is pissed off and the tranny leaks like mad. If Rpm's are perfect it shifts like a champ but otherwise does not like to go into 2nd. Downshifting from 3 to 2 is also not really an option. Any suggestions or Parts suppliers out there who can help??

The first step is to find-out what Mopar 3-speed is in the truck.
Once you have that info., call around to see if there are any used or rebuilt boxes available.

Sounds like you need a rebuild, a second gear syncrow, bearings and seals.
DD