I just did a little researching on your 4 speed. The #3845106 is one number off that I am showing, my manual is showing #3845107.I don't know if this would be close enough or not? If so here are your trucks. 55-59 1 ton /4 speed.(2nd Ser.) 59 1 1/2 ton w/4 speed 60 Ser. 10 thru 40 w 4 SPD. 61-62 Ser. 20 thru40 w/4Spd.(exc.4 WD) (use with /8x21/2 inch prop. shaft brake. Also 55-59 3/4 ton w /4 spd. (2nd Ser.) :p
