AT LAST….. 5th gear has arrived…. in the shape of the Canadian Rock Mountain Overdrive. It used to be called the “Roverdrive” but Land Rover didn’t like that, so the name was changed to the “Global Roamer Overdrive”.
The overdrive is a Power Take Off (PTO) unit. A variety of devices can be run from the PTO on the back of the transfer box, (winch, compressor, hydraulic pump, welding generator, lawn mower, under drive, over drive, additional prop shaft to run a belt drive from the rear cross member, further extending the ability of the vehicle… corn thresher, circular saw etc. You can’t do that with a Pius… sorry… Prius) and one of these devices will allow you to have a 5th gear.
The overdrive is a gear totally independent of the rest of the 4 speed gearbox and operated by a separate gear lever. In normal driving conditions, one would drive sequentially through the main box (1st, 2nd, 3rd ,4th) then engage the overdrive (5th). It can also be used as a splitter gear between all 4 gears (and reverse) in the main gearbox… for example1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5.
The overdrive increases gearing by 28% which makes motorway driving far more comfortable and also (in theory) improves fuel economy and reduces stress on the major mechanical components.
PLUS…. it means theres a 4th gear lever in the cab 🙂
But installation was not without issue. I cannot, for the life of me, get the overdrive to go all the way onto the coupling…. and I know exactly why. It’s easy enough to slide the coupling together on the bench but once you’re under the vehicle…. its a different kettle of fish. I’ll leave it for a couple of days and have another tinker with a fresh pair of arms… The overdrive is not the lightest of units.