I’ve been reading the SC430 forums for a few years and have finally decided to join the forums. Last July I got lucky and found a great deal on a 06 silver/black leather beauty with 3K miles through a private sale.

Had a Lexus dealer run the certification inspection and vehicle checked out as new. Since then I can say that in my experience the SC430 is the "best all around vehicle" in its class and before making my purchase I did drive all the competition.

My question for my opening post is that I noticed that for the 02-06 model years the SC430 final drive ratio is listed as 3.27:1 but in the 07-08 years Lexus has changed the ratio to 3.769:1.

Can someone please explain the ratio change in reference to the timing of the gear changes, overall performance and gas mileage? Thanks.

 

Welcome Vito,

As for the change you have noticed, the 02-06 models all have a 5 speed transmission as opposed to the 07-08's who received a 6 speed transmission.
Now to the rear ends, if you have a higher ratio in the back with our cars 02-05 you will notice an increase in power and you will also notice that your rmps at highway speeds are about 800 higher, causing lower miles per gallon.
With the new 6 speed revision they were able to put a higher ratio in the rear pumpkin while still keeping the great fuel economy and comfort of the car.

 

Thanks Lexiss for your feedback but FYI the 06 does carry a 6 speed transmission. Given a 6 speed transmission how then will my 06 compare with your 03 and say an 07-08? Interesting that Lexus chose to maintain the 3.27 ratio for this model.

 

Well in that case your car should have better fuel economy then our 5 speeds, from a dead stop I would imagine we would be neck and neck, from a roll you might be a little quicker since you have more gears to choose from.
But the 07+ should give both of us good run. Their fuel economy should be worse than yours, but they should be quicker than us all around.