If you were wondering what the do's and don'ts are with the 4R70W or want to rebuild your existing tranny to make it bulletproof have a read of these articles:
http://www.tccoa.com/articles/tranny...on/index.shtml

The article is for Mustang/Cougar but most of it applies to our trucks as well.

User "bjherron" from the www.fordf150.net forums posted this link originally. It's great reading.