Finding & Fitting a Roverdrive

1st off, eternal gratitude to TSD for finding this on eBay and not buying it for himself as it was a total and utter bargain. Also for helping to fit the blessed thing in a cow-shed.

The Rocky Mountian Roverdrive (now called Roamerdrive, presumably thanks to JLR's over-zealous legal department) has an excellent reputation1) (as does all their stuff) but by crikey are they spendy - as of writing they're about £1800 to buy new!

The original transfer box in the ambulance made a very annoying whine - my guess was the input gear had been replaced but not shimmed - which went right through you. Also the gearing was a little low for relaxed cruising. In a perfect world I'd have bought a Roamerdrive, but my realistic expectation was to replace the original 1.410:1 ratio LT230 with a 1.222:1 unit from a Range Rover or Discovery.

Anyway, long story short, TSD found this Roamerdrive on eBay attached to a 2006 Defender drivetrain - a TD5 engine, R380 gearbox and 1.410:1 LT230 complete for (far) less than the price of a Roamerdrive on its own! The terrible and timeless curse of eb'aay was uttered: “You'd better buy this before I have to”… and so I did. :rolleyes:

Here's the unit as it arrived:

And here's all the leftover bits!


Fitting is fairly straightforward although it does involve big heavy oily lumps, and in our case involved an already-hacked-about Defender floor & gearbox tunnel.

You do need the proper oil (pure GL4 with no aggressive GL5 / hypoid additives) for the unit, and it's advisable to splash out for RM's extended & finned sump to help cool the LT230 and increase the oil capacity. Beware the heat from the exhaust though, as we find out below!

Posh synthetic GL4 might be worthwhile, further oil cooling might also be worthwhile depending - as always, step 1 is to decide if things really are getting too hot or not. Temperature labels are your friends.

The only issue with out setup was the floor had been “hacked” to fit the later R380 gearbox (previous owner, I'm glaring at you!) so the tunnel etc. was a poor fit, which totally fouled the overdrive lever:

Thankfully, we know a Mike who is a God of fibre-glass and can be bribed with little pieces of paper with pictures of the Queen on, here we see the original and the new improved tunnel:

And here's the new improved one getting some reflective sound-deadening insulation attached:

As our seat-box had also been hacked around I had to add a small filler strip, I added the aluminium tape over the top to cut down on draughts - you won't see it once all the mats are down:

And voila!

The sound-proofing stuff has made a huge difference to noise & the temperature of the cubby box, very pleased with it, would heartily recommend, etc. etc.


First test outing was actually the run to Monaco. We hadn't managed to close the gap in the transmission tunnel so it was a bit noisy, that said, it was less annoying than the old whining box and provided very civilised 70mph cruising, and one fuel stop we topped 20mpg, which is not bad at all for a big dumb V8 in a big brick-shaped thing.

We wanted to make good time on the way down so were cracking along at or around the speed limit of 130kph/80mph (honest, Monsieur Gendarme!) despite some fairly prolonged 5-10% climbs on the route. The temperature labels went off the top (110degC) which is not ideal, my theory is that being next to a red-hot exhaust doesn't help so I'm planning on knocking up a heat-shield before the next trip. Off the scale, not a good sign!
You can see how close the exhaust is to the big heat-sink, possibly not optimum!


I added a heat-shield to the exhaust which does seem to have helped, I've also keeping it below 90mph in case that should matter.

Heat-shield design & fabrication process involved bending a bit of aluminium over my knee and digging out two exhaust clamps to hold it on:

As you can see, it's made quite an impact on the temperature recorded:


GKN overdrive issues or “why I am glad I have the Roamerdrive”.

Unlike the GKN unit
alfie/roverdrive.txt · Last modified: 2019/05/20 14:42 by jin
Driven by DokuWiki Recent changes RSS feed Valid CSS Valid XHTML 1.0