I have a 97 F150 4x2, supercab short bed with 266k, she runs great and i haven't had any real problems with it other than routine maintenance. It has a tow pkg with the tranny cooler. I wanted to know if anyone has ever flushed the transmission before, and how you did it. What type of fluid did you use? synthetic(redline), a synthetic blend? What would be a good one to use, or does it matter?

I am also considering replacing the entire exhaust from manifold to muffler with and whole new system. however i have been told that i can't remove the cats or replace them with anything other than the original factor cats otherwise the computer some how know and it won't run. Is that true? and if it is does anyone know of a way to bypass this? I would really like to run headers, through 2 free flowing cats, instead of the 4 it has now, out a flowmaster, and do it all through 3" pipe, instead of the 2.5 it has stock.

Lastly, does anyone know of a good brand of headers to get for a 5.4? I know summit has some, and so does gibson. I haven't heard anything good about gibson and nothing about the summit brand.