I have a T18 in my 72 F250. I rebuilt the transmission about a year ago with a Novak kit. I didn't drive the truck before I rebuilt the transmission, though, so I don't really have a "before the rebuild" point of comparison, but whenever I try to downshift 4 to 3, the transmission grinds like mad, as though there's no syncrho in there at all. If I pop it in neutral and slow down a bit, then rev the engine a little it'll slide right into third. The dang thing does the same thing if I try to shift at "high" RPM (and by that I mean 3k-ish). It shifts into third just fine under other normal driving conditions.
I'm thinking maybe a poorly adjusted clutch?
Also, reverse on this one is right and down, so I know I'm not hitting reverse on accident.
Thanks!