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@ Ontheroad mentions having your LS400 in overdrive. What do you mean by "overdrive" ?. My '96 400 doesn't have overdrive. Just PWR ECT.

Paul

Top gear is effectively over drive (need to look at the gearing though) for a LS. A LS is automatic so the torque converter can "slip" a little - however at high speed in top gear it will lock up which is the best approximation to overdrive. Top gear is usually direct drive and an over drive gear used to be fitted to manual cars with 4 speed gear boxes to over gear the car - you could not reach top speed but cruise at high speed and low engine revs.

Five or more gears are now common so the highest gear can be overgeared to give you an overdrive - in the old days manufacturers bolted and extra unit on the end of the gear box however I'm not sure if they do anymore becuse I am too fat and old to crawl under cars - also I am an electrical and electronics engineer so lazily pay other people to mend my LS :)

Bren

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@ Ontheroad mentions having your LS400 in overdrive. What do you mean by "overdrive" ?. My '96 400 doesn't have overdrive. Just PWR ECT.

Paul

On the original Mark 1 the overdrive function was discribed as that by Lexus in the Manual and it was also inscibed on the switch embedded in the gearknob which you pressed to apply, mine was applied always but electronically controlled did'nt operate under certain driving conditions.

The car only had three forward gears low 2nd and drive,this meant you could actually do 100mph in second gear and I did (naughty).The overdrive would only come in wether switched on or not when the car was cruising above 30mph and the transmission fluid had warmed up and did'nt operate in the ectpwr mode at all, it is as Bren says a slightly higher ratio gear than final drive.My 98 LS as a 4th gear and then a flick to the left on the gearknob too drive which I presume is overdrive its just an extention of gearing to the original ls and they have dropped the overdrive word.

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@ Ontheroad mentions having your LS400 in overdrive. What do you mean by "overdrive" ?. My '96 400 doesn't have overdrive. Just PWR ECT.

Paul

On the original Mark 1 the overdrive function was discribed as that by Lexus in the Manual and it was also inscibed on the switch embedded in the gearknob which you pressed to apply, mine was applied always but electroniccaly controlled did'nt operate under certain driving conditions.

The car only had three forward gears low 2nd and drive,this meant you could actually do 100mph in second gear and I did (naughty).The overdrive would only come in when the car was cruising above 30mph and did'nt operate in the ectpwr mode it was as bren says a slightly higher ratio gear than final drive.My 98 LS as a 4th gear and then drive which I presume is overdrive its just an extention of gearing to the original ls and they have dropped the overdrive word.

Interesting Paul - I never owned a MK1 400 so never saw the switch. The 5 speed LS430 has a final drive ratio of 0.753 to 1 and the 6 speed 0.58 to 1 - which are both overdrive.

Bren

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I just leave mine in "D", does that mean it is going into overdrive at high speed? What is the ratio of 4th gear in a Mk 3? I'm slightly confused by this!

Paul

Hi Paul yes to your overdrive question

A 4 speed 1989 has a 4th gear ratio of 0.75 to 1 - as you can see below 3rd is direct drive so instead of the old bolt on overdrive unit and a button they built a new gearbox and put in a forth gear and over geared it so you have overdrive. The five speed box has 1 to 1 in 4th - they now have 8 speed boxes and 1 to 1 is 6 so you have two over geared ratios.

Gear Ratios for 4 speed LS400

Gear Ratios: 1st 2.450 2nd 1.450 3rd 1.000 4th 0.730 Reverse 2.222 Final 4.300

Gear Ratios for 5 speed LS400 and 430




  • The A650E five-speed automatic had a 3.357-to-1 first gear ratio, a 2.180-to-1 second gear ratio, a 1.424-to-1 third gear ratio, a 1.00-to-1 direct fourth gear ratio and a 0.753-to-1fifth gear ratio. The reverse gear ratio was 3.266-to-1.

Top gear is overgeared so is an overdrive for each car.

Bren

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Just to add to this discussion, my 1999 auto Land Cruiser Colorado has most certainly got gear changes that are more noticeable than the Lexus!!! It is a 4 speed unit and has the overdrive button on the side of the shift control. The lock up shows a definite fall in revs at an indicated 52 mph (around 50 on the sat nav) and only operates after a couple of miles when the fluid has warmed a bit. Sad to say I can predict lock up as I drive along known roads to within a few hundred yards according to the ambient temperature!!! This is sad and fails to impress my wife. The PWR ETC button disables lock up.

Mark.

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  • 2 months later...

Thanks to this great thread i am back on track looking for a LS 430

i googled lots of places and was really disappointed with the bad MPG

then the penny dropped

i was directed to lots of USA sites and there the US and UK gallons are different

so the MPG was reading really bad

this has inspired me to keep looking

got two to see on saturday

what has amazed me is how many people selling these cars have ooppps lost the service history

or oh yea its a cat c bla bla bla

will update as and when i get mine

and a big thanks to all who took the time to keep this thread going

Gaz

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Thanks to this great thread i am back on track looking for a LS 430

i googled lots of places and was really disappointed with the bad MPG

then the penny dropped

i was directed to lots of USA sites and there the US and UK gallons are different

so the MPG was reading really bad

this has inspired me to keep looking

got two to see on saturday

what has amazed me is how many people selling these cars have ooppps lost the service history

or oh yea its a cat c bla bla bla

will update as and when i get mine

and a big thanks to all who took the time to keep this thread going

Gaz

Before you jump you might like to read the currant thread entitled "Im Really Beginning To Hate My Ls430" Mike

"

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