first its an inline 6. in 86 i believe they started putting 5 spd in the F-150, so you could have either. look at the knob for starters, if that dont do any good then feel the throws in 1st and reverse is there a lot of moving in the stick in order to get it in gear and are 1st and reverse really low gears? also does it have an external slave cylinder? underneath the shifter boot is there a cup shaped thing that screws onto the top plate of the tranny? if any of those are so then its a 4spd. also most 4 spds were cast iron with the exception of one model 4 spd. if not then it very well may be a 5spd. 5spds were all aluminum the bellhousing, gearcase, and transfer case if 4x4and all.
