Further to our discussion ^^^ re the gearbox in the R Collin preservation NGC I am reliably informed by those who inspected the vehicle today, that the original gearbox was definitely an RT9509A. It had been modified, probably when new, with an Eaton 13-sp conversion kit. Such a kit includes a replacement complete 3-speed auxiliary housing that’s fitted in place of the 9509’s 2-speed unit; and a replacement 3-position hand selector valve – ie gear knob – and the associated piping. This converts the RT9509A gearbox into an RT9513A (non-overdrive, you’ll notice). Apparently, it is not possible to convert an RT to an RTO without changing the gear sets in the main gearbox. This was very seldom done because it would be easier to swap the entire gearbox over.
My grateful thanks to the chap who took the time and trouble of apprise me of these facts.
Robert
