I know it's no lockup, that's not what I was asking, I'm asking what's the difference between the gears? I can't really find any for sale that as marked below 78. I appreciate it though.
This should help.
904 pump gears. lug style. 1960-2003 : The type you have.
904 pump gears. Milled flat style. 1993-2003
My catalog shows no size differences listed for either type(one size fits all in both cases?), just they two types, lug or milled flat.
It makes no difference if the transmission is a lockup or non lockup.
The rear clutch spring is listed for 904's from 1960-2003, but I don't know that they were in all 904's, although we did sell a fair number of them.
