77 Midget, no reverse lock out

Subject said it all.  The reverse lockout is not working on my
77 Midget.  The only reason I can think of is that the shifter
ball is not down far enough into the transmission.  What might
cause this?  Any other ideas?  The car now runs and pulls 
pretty good around the neighborhood.  Can you believe that the
local police had some questions about the missing bonnet!
When I took him to check out the seats, which were not bolted
in, he gave up and sent me home :-)

Bill Gilroy