This CY50 is an old 1964 5klb with holden 6 motor (factory fitted from new)
(unit is actually a CYF50 (Friction clutch) but has had transmission changed to auto long time ago.)
The machine is for home use & gets very little work.

I get serious transmission slip when engine is hot (winter use no problem) both forward & reverse.
Have to wait for cool down to drive again.
I checked tranny oil pressures & are within spec. (didn't check when slipping though will try again)

Is hot slipping an oil pump problem or friction plate wear issue ?
I don't have time to rebuilt right now but might try "transmission fix" additive.

Any further info will be helpful
Thanks