Thread: OverDrives - GKN - Roverdrive - 6 Speed

Afternoon, yes its true the GKN on the Tdi is not the best option...we are waiting on the word from the UK on the 6 speed box...it with have an adaptor to fit the Tdi (300)...not sure on the other specs butdo know they are having a bearing problem and we won't see boxes till mid to end of the year as they are all being used on the production line...

Stuart

Originally Posted by Michael2

Does anyone on this forum have an overdrive on their Defender?

I've been reading about the GKN unit and rang Ritters today to get a price, $3,500 + GST + Fitting. I've seen them for around $1,900 ex-UK (pre VAT). The guy I spoke to at Ritters didn't think the GKN would be that useful on a 300Tdi, as the 300Tdi didn't have as much power as the TD5. He suggested that next years 6 Speed Defender gearbox would come in at about the same price as the GKN O/D and would be a better proposition.

Another option is the DX Roverdrive, at about $1,700 (retail) ex-Canada. I've emailed inquiring about a pre-Tax export price. This unit seems to have a really good gear engagement and is lubricated from the Transfer Case.

Whilst the GKN is electronically controlled with a computer override to disengage when power drops, the DX unit is lever controlled. Much more simple, but another hole in the floor and another gearstick and set of linkages to rattle.

Anyway, if anyone has info on either of the overdrives, or info on the 6 speed box (ratios, will it bolt straight in? will the mounts need changing? will the tailshaft lengths need altering?.....) please comment.

http://www.devon4x4.com/news/26

http://www.wiseowlparts.com/

I also have read an article on the GKN overdrive unit. They feel that it is covered for a Defender and were looking at putting one on a Discovery Td5.

And thats the last I have heard for about 2 years

Cheers.
Lyndon.

Originally Posted by Michael2

Does anyone on this forum have an overdrive on their Defender?

I've been reading about the GKN unit and rang Ritters today to get a price, $3,500 + GST + Fitting. I've seen them for around $1,900 ex-UK (pre VAT). The guy I spoke to at Ritters didn't think the GKN would be that useful on a 300Tdi, as the 300Tdi didn't have as much power as the TD5. He suggested that next years 6 Speed Defender gearbox would come in at about the same price as the GKN O/D and would be a better proposition.

Another option is the DX Roverdrive, at about $1,700 (retail) ex-Canada. I've emailed inquiring about a pre-Tax export price. This unit seems to have a really good gear engagement and is lubricated from the Transfer Case.

Whilst the GKN is electronically controlled with a computer override to disengage when power drops, the DX unit is lever controlled. Much more simple, but another hole in the floor and another gearstick and set of linkages to rattle.

Anyway, if anyone has info on either of the overdrives, or info on the 6 speed box (ratios, will it bolt straight in? will the mounts need changing? will the tailshaft lengths need altering?.....) please comment.

http://www.devon4x4.com/news/26

http://www.wiseowlparts.com/

had a mate in the Uk that had it on a TD5 90. Said it was grerat but cost him 1000 pounds fitted. But he did have a JE stage two chipp. Thats full intercooler and bigest upgrade chip. Thing went like stink. Would do 0-100kph in 7.5 secs That was test by Je as fact. mmm as they said fast tractor. with the over drive it would cruse on the motorway at 193kph
mad amd 90


BTW GKN is the main and only importer of ARB in the UK. Question is its it a two way thing . In other words can ARB get cheap GKN stuff

Mike, I have the GKN fitted to my 05 TD5 110. I imported it myself from Simmonites (UK) and landed price with tax was around the same ($3400 as I recall). I only imported it myself as Bruce Davis (who fitted it) couldn't get any stock as the UK LR shows had snapped up a lot.

The reduction in noise and revs is very impressive. At 110 with the GKN it revs at about 2200 whereas it was probably around 2700-2800 before and a lot more noisy.

Combined with the full Davis tuning pack (3" exhaust, bigger intercooler, chipping - total ~ 180kw/550nm) it now cruises effortlessly, and fuel consumption is down under 10L/100 on the HWY (even lower if you run at about 100, rather than the 110-120 I now do, fully laden with a 400kg Hobie Cat and trailer in tow).

I can only sing its praises, and combined with the Davis tune, the vehicle is unrecognisable. We had some astounded glances from various passenger cars and 4x4s we steamed by ascending the Ourimbah hill coming back from Myall.

I believe Bruce now has stock again. He's also working on a map to enable the fitment of the Disco cruise control to the GKN OD (Bruce has installed both the tune package and the GKN in his wife's 90).

So, Gavin, from your experience; and Reads, from your experience with your mates 90; do you think a 300tdi will benefit from the overdrive? My Defender only has 120K km on the clock, so I guess it's going to be a long while before I need to upgrade the turbo (I'd fit the turbo & intercooler from a 2.6HS if I did). I've got a Fairey OD in the SIII, which is powered by a sewing machine motor, that works fine cruising at 110kph, but that's dropping the revs from 4000 to 3000rpm.

Any opinions on the 300tdi's ability to cope would be appreciated.

Originally Posted by Michael2

So, Gavin, from your experience; and Reads, from your experience with your mates 90; do you think a 300tdi will benefit from the overdrive? My Defender only has 120K km on the clock, so I guess it's going to be a long while before I need to upgrade the turbo (I'd fit the turbo & intercooler from a 2.6HS if I did). I've got a Fairey OD in the SIII, which is powered by a sewing machine motor, that works fine cruising at 110kph, but that's dropping the revs from 4000 to 3000rpm.

Any opinions on the 300tdi's ability to cope would be appreciated.

In ther UK yes in Aus NO. In the Uk we drive along the motorways at 120 kph to 155 kph. so the gearing in a landy runs out.,
However here in aus i think you will find it will be over geared and the gear will work like a brake in other words you will put it into overdrive and you will slow down. Bit like the 5th gear on a 2.5 petrol defender

If you have money burnig a hole in your pocket i would buy a full size intercooler and a set of silicon hoses. And that will impove the power no end. Would be like a differant truck

Mike, couldn't comment specifically on the 300TDI's power, but my own experience of the GKN 6th gear is a much better highway experience. Might be worth speaking with Bruce Davis directly on 02 9679 1978. If you're in Sydney and would like a bash on mine I'd be happy to oblige - just PM me. Gav

Originally Posted by gavin_ger

Mike... If you're in Sydney and would like a bash on mine I'd be happy to oblige - just PM me. Gav

Thanks Gav, I'm in Melbourne unfortunately, - but that's a very generous offer. I'll call Bruce Davis and see what their experience with the 300tdi is.