If it is a manual it is called a New Venture 4500, I dont know what the automatics are.
+4 trans fluid
No, the 1997 has an electronic governor. The 1994 has an hydraulic governor.
Yes, the transmission from a 1996 Dodge Ram 3.9L will fit into a 1997 Dodge Ram 3.9L. They will both have to be automatic, or manual shift, though.
ATF+4
1996-1997
It does not have a modulator
The automatics use different shift controls and are not interchangeable.
Down the trans dipstick tube.
10w30
You need to put a little more detail in. What engine do you have, and what engine did the 99 have?
46RE
Auto is a 46re Manual is a nv3500