My tranny is going, overdrive is gone and I get slippage from 2-3. I've
changed the fluid and filter to see if that helps, but nothing.

I'm thinking of finding a used tranny. I don't have the money for new
one. Is there any chance that a later model tranny will fit on a 99
Dodge?

Also were is the tranny model located? There seems to be several
trannys for this  vehicle.

Specs
99 Doadge Ram 1500
5.9L
2wd
Automatic trans w/overdrive

Thanks