Think maybe it's time to change the gearbox oil...
...in trying to locate the drain plug I consulted my old Haynes manual but I can't quite find a plug "underneath the right-hand side of the gearbox in an inclined position".
I'd be grateful for any help.
Also what oil would you recommend?
How about an 'engine flush' type product prior to the change - worth it?
Any assistance gratefully received.