Ok guys, I found out what size rear end i have in my 99 f150. Its got a 9.75", 34 spline, same as in the 250 and 350. I guess they are starting to put this unit in the newer f150's. Where is a good gear shop to go to in the O.C. area. Need to have the gears, bearings and seals done. I am keeping the stock posi though.