Overdrive ?

[Flames]

Hi Everyone,

In an effort to improve the overall fuel economy on our 2004 RX 300 (Mk 2) I have been surfing the web and the owners manual on the subject of overdrive. The owners manual says it's fitted, but unlike the Mk 1, there is no switch.

So my question is "how do I engage overdrive when cruising on the motorway ?" or will the car select it by itself ?

I've looked through the forum but I seem to have failed to find the answer.

Also - anyone had a re-map to improve economy - or is it a myth that the economy can be improved by re-mapping.

Any help or advice appreciated.

Regards

[steve2006]

Hello and welcome to te LOC.

On modern transmissions you will normally find the highest available gear and occasionally the top 2 gears is/are overdrive gears and in an automatic transmission will be selected as part of the normal shift pattern.

So for example when in 4th the ratio may be 1:1 and 5th (top) could be 0.88:1 ( in other words an overdrive gear).

Believe it or not Lexus engines are tuned for economy from the outset, there is not a lot you can do to improve it apart from sensible driving tecniques, performance mods maybe but not economy.

If you look at the engine specifications for the LS400 V8 engine in standard guise the BHP is around 250 but it is said these engine can be retuned to acheive nearly 1000 BHP on a standard crankshaft, in other words they are lazy but considering the size economic engines, another reason is they have been known to do 500,000 miles without major issues.

[Flames]

Hi Steve,

Thanks for that. Just done a test drive and 5th in manual mode is the same rpm as D, so I'm thinking it engages it automatically, as you state.

Regards