Hybrid gearbox

WE GOT in quite a pickle over this one. We’d sourced a Discovery V8 LT77 gearbox to combine with the Ninety’s original LT77 gearbox that had run with the original diesel engine. We needed the V8 gearbox for the longer bellhousing which we planned to remove and fit to the original box, along with the extended gearbox input shaft. Using this configuration means the V8 engine would sit nicely forward in the engine bay, clear of the bulkhead. We couldn’t use the complete Discovery gearbox because on that car the gear lever is positioned behind the high/low lever, whereas on the Ninety it needs to be in front.

Strictly, a 1989 V8 Ninety should have the LT85 gearbox (also known as the Santana box), and Trevor Cuthbert had one available that needed an overhaul. It’s a strong box, but only four-speed and the change is a bit clunky, and spares could become difficult in the future, so I stuck with the LT77 plan.

So we dismantled the two LT77 boxes to change the parts over, and that’s when we found the gear on the Discovery unit’s extended input shaft had one fewer teeth than the gear it would mesh with in the Ninety’s gearbox. Undaunted, we set about swapping the layshafts, and that involved removing the fifth gear housing at the back of the gearbox, resulting in a complex spread of gearbox components across the bench. I think a third gearbox entered the fray at one point, but none of this was working because the LT77’S multiple upgrades during its production life meant that differing bearing and shaft sizes denied any chance of compatibility.

I contacted Ashcroft Transmissions who could build me a version of the later R380 gearbox to suit the V8 and with the correct lever orientation, which would have been a good upgrade. But I struggle to use the R380 box on my 110 due to a shoulder injury from mountain biking and, for that reason, prefer the LT77.

Luckily, Steve had been attentive in keeping the dismantled gearboxes separate from each other. So he rebuilt them loosely and we sent both boxes off to David Beaumont 4x4 who turned them into one overhauled gearbox with extended bellhousing and input shaft plus a Defender-style fifth gear housing to give the correct lever set-up – perfect. Our gearbox strip was worthwhile though, both from an interest point of view, and the learning experience – it’s most definitely the best way to understand Land Rover things.