Grab a Chilton's manual or a Chevy shop manual for your truck. You will have a lot of fun doing it yourself and you will learn alot and appreciate it more. I rebuilt a 3 speed trans out of a GMC using a Chiltons when I was just 16! Give it a try!
Brett


'50 Chevy 3100 http://www.flickr.com/photos/34731099@N06/?saved=1
'63 GMC, gone but not forgotten!