Transmission fluid change

I have a 1996 V6 S-10, I want to change the fluid in the manual transmission. Problem is no one will give me a straight up answer on the fluid type or number. My haynes book says that I have a New Venture 3500 transmission and gives me a photo of it. The drain and fill plugs don't look the same in the photo and on my truck. I have about 1" hex plugs on mine, one at the very bottom and one about 3"or 4" above it, do these resemble a NV3500? I can't find any #'s on the transmission, but they might be hidden. So, is my transmission a NV 3500 or is the picture wrong? and, what do I put in it? Any suggestions would be great, thanks.