'94 f-150 trouble code 636
 

I have a'94 f150 and the check engine light came on, it is code 636( transmission temp out of range), where is the trans temp sender and how do I check it. it also vibrates little bit when it shifts into 4th, I don't feel like dishing out the money for a new transmission or taking it to a shop, my dad is a mechanic so we are capable, but how hard is it to overhaul a e40d, also has anybody here used lucas oil transmission fix.