Yup, they take ATF. The caps on these pumps suck from the get go and I'm not surprised everytime one of mine blows off. The cap on my PSD blows off once a year and the cap on my F-150 blew off once when I accidentally forgot to set up the rev limiter and over revved it while testing it in the mud.
Travis- Death Row Diesel Inmate #7
1995 F-250 RC PSD- because race truck
2000 F-250 SC LB 4x4 ZF6- 4" TB, 6637, TW and Gearhead tunes, 160/100s, Driven Diesel full fuel system, S365..
1994 F-150 4x4