I prefer the external slave as well. But the real question is, can a NV4500 be swapped into a truck that was made before it was? (without major modification)
So I bought this single cab longbed truck a year ago and broke the reverse gear in the 5lm60 manual transmission. I opted to rebuild it myself since my budget was pretty limited at the time. It was a difficult rebuild, but I got it done and back in the truck. It wasn't a perfect job either...