1997 Ford F-150 paid a donation and no reply within 24 hours

Hello and thanks for replying this is the first time I used this site so I wasnt sure about duration of answers. Well here it goes I bought a f150 that needed a tranny it wouldnt move at all. I bought a used one 4r70w and it was exact match to tag(called dealer for the id). Had the tranny swaped out and it works it shifts through all gears to overdrive and if I push the overdrive button it will down shift to drive and back into overdrive if I hit button again. BUT after it shifts throough the gears I am going 30MPH and tach reads 3000 rpm and whines like I was driving in second gear or something. AS for the transfer case its works properly going from 2wd to 4wd and so on. The best way to explain it I guess is it works but I am in low range 2wd? Any input you may have will be greatly appreciated. The only other info I have is a friend did a code read and all we got was the rf sensor was working (the sensor on shift selector) not sure if rf is proper name lol.