Ford ZF Truck 6 Speed 7.3L 1998-on S6-50 Input Shaft Drive Gear Part# ZFS6-16 Fits 1998-up F250, F350, F450 and F550 F Series Truck with 7.3 Liter Diesel Engine This shaft will fit your transmission If you have the following tag numbers. ZF Part # Description Unit Specification (1319 050 ___) 004/005/006/022/023/024/025/036/037/045/046/049 .670 Pilot Tip diameter 1.350 clutch spline diameter 1.578 seal surface diameter 2.00 Bearing surface diameter 23 Gear Tooth Count 48 Synchro tooth count 10 3/8” OAL This transmission input is for a Ford ZF Truck with the 6 Speed transmission that has an aluminum case and is rear loaded. This transmission will have a cast of "1319" on the case.