Transmission question

[hollywood763]

The transmission in my 66 3/4 ton truck is a 4sp with a granny low, and I'm replacing that transmission with another 4sp granny low that's out of a 66 half ton.
will this swap strait across or is there a difference between the half ton trannys and 3/4 ton trannys to where there has to be some modifications made?

I found this transmission on craigslist and I don't want to bother with buying it unless it's an easy swap.

thanks.