transmision identification

[johnnyUK]

Hi All,
I need to identify the gearbox fitted in my 1972 F100, so I can order up some parts for it.
It is leaking oil from the front input seal or gasket.
I know it has been converted to a 4 speed overdrive RUG with a Hurst shifter.
The Tag on the Gearbox is RUG OD JJ22 D 8TR MA 2336

What do all the digits mean?
Thanks,
Johnny