Overdrive Installation, Land Rover Series

[wings&wheels]

A few pics from installing an overdrive in the LR. I occasionally drive this on the highway and the OD gives a ~30% reduction in RPM and reduces fuel burn and noise. May also extend top speed but you probably d/n want to go much beyond 60mph in one of these.

Neat view of the transfer case showing the straight cut low range gears, selection mechanism and transmission brake. In the top pic, the transmission (front) is to the left and the OD uses a co-axial gear to take the input into the shaft in the gear center and step it up to the outside output gear you see below.

 

[Barkleymut]

Did you calculate the gas savings? What are the rpms at 65?

 

[HerrStig]

The Laycock unit I had on several Volvos could be wired to work on all foward gears. First wouldn't engage because the pump which drives the works is driveshaft driven. I used the "xtra' gears for autocrossing. (and to sound like a semi accelerating, which occasionally turned the heads of professional drivers)

 

[wings&wheels]

assuming my calcs are right, i have the larger tires off the longer wheelbase "109" model, i would be at ~3700 rpm at 65mph. with O/D engaged i would be ~2,700.

no idea on fuel consumption impact from the O/D yet, not something i really track, but i would guess that i get 13-15 mpg now.

this O/D, the Roamerdrive, can be used in all gears in all ranges. it is a clever unit that uses the planetary gear-set from a THM400 and a Land Rover synchro w/ some standard bearings, etc., all easily obtainable. It's design is similar in concept to the Layckock/GKN/Gear Vendors units except it is mechanically actuated and seems more robust. it is also the only current production unit available for LR Series.

 

[wings&wheels]

this pic dropped off after a few hours...weird. it's the one i reference in the text

 

[Silk]

Used to see them on the Series IIA often - a Holden 6 cyl conversion was popular over here, and as the Holden revved lower than the Landrover 4 cyl, top speed was down...an overdrive cured that. I used to shift them like a twin stick truck.