I hate when people say that. You dont know how qualified he is or what is capable of. He might have a complete shop with all the tools you could ever need.
Generally, I hate it too. But the wording and subject matter of the OP's question makes it plain that he has neither the knowledge, nor the tools to perform the work without a LOT of coaching, and if you've ever done rear end work, you know what I mean. I'd hate to see him trash his gears, or expect to get the job done on a Sat. night and then have the truck apart for three weeks due to difficulties.
That said, I think that the very best shop manual is Ford's own. I have one, and it's about four inches thick. Available at Helm, Inc.
They're not cheap, but they're the best.