what is a good site to get a symatic of a 99 for f150 rear end. I got a big leak and need to rebuild it?

Answer 1

This is too technical for such generic information. Different models and manufacturers build the differentials differently, and disassembly and reassembly are not necessarily the same from one model or design to another.
The best thing to do is to either purchase a repair manual for that little pick-up, or go the library and use theirs (in the REFERENCE section).
For computer based data, go here-------->

http://www.eautorepair.net/

...and for an annual subscription fee, you can have access to ALL of the published repair information for the vehicle. Very good stuff. Professional level.

Good Luck