So I changed the tranny fluid yesterday I work at a lube shop and we only have 80 90 gl5 so I used that shifted nice until it cooled overnight.... I could get it into second easily at all for a few min. I know ford honey is the best choice and I have been told royal purple syncro max is a great choice also.... Both are 20 a qt at the dealer and the rp is 20 a qt at autozone any cheaper alternatives I can buy that will still provide a very smooth shift? No ATF please!