Where to get a front pump for a 42RH (A500)

So my brother's birthday is coming up and he has an old 94 Dakota V6 that was his first car and it's been showing its age pretty bad lately. I'm fairly sure the transmission is mostly junk, so I wanted to rebuild it for him as a present, but I'm having a bit of a hard time decoding all the different models and what parts will swap between them. The little V6 doesn't make any real power. so upgrading isn't really a concern, just a rebuild with lots of new parts. The truck is a 4x4 however, for what it's worth. I think the biggest problem with the unit is the front pump. I don't think it's making much pressure any more, so it's pretty sloppy on gear changes. The only pumps I've had any luck finding are on Ebay and are listed for a 42RE, the electronically controlled brother of the 42RH from what I can find. Are all the A500 series pumps the same and swapable between the different models, or do I need a pump specifically for a 42RH? Aside from that, any recommendations for a good rebuild kit and basic converter?