|Apologies if this is a repeat question, but I've read up and am confused about Gearbox + Overdrive options. I'm not that interested in the Toyota 5spd conversion.
I understand that the Rootes H120 gearbox (that had overdrive) can be fitted to the JH, but is it the entire gearbox, or just the overdrive box? I am running a stock 4spd with ~90k miles on it, and it's weeping oil from the seals, so is due a rebuild (it's completely smooth otherwise).
I figure that if it's an easy swap (and I can find the parts) I may as well fit the O/D whilst the gearbox is being overhauled.
My other question is whether the Rootes O/D is the only option, or whether one from an MGB/Spitfire could be used as they are more plentiful...). They both seem to be Laycock type units. Apologies if that is a really dumb question...
For reference, my JH is unrestored, aside from maintenance, and a couple of engine rebuilds (years ago) and a conversion to Dellorto's, so she's pretty much as she came from the factory in '74.