LouB

The salesrep that sold me my 08 rx350 said shift position D4 will give better gas mileage for around town driving. The owners manual only refers to D4 as minimal engine breaking...D3...D2 as progressively more engine breaking. What is the difference between the D and the D4 shift position and will it provide better local gas mileage? Does anyone know?

Booyah

Never listen to your salesperson most of them are clueless and looks like you found one too--leave the tranny in D and it will shift whenever it needs too,
D=overdrive
D4=basically 4th gear

Arbitrage1

The manual says D4 should always be used when towing. It also says that D should be used to obtain optimal gas mileage.

Personally, from someone whos only ever owned manual transmission cars, when I drive in town I use D4. I do this becuase I dont like how it shifts into 5th at 35 or 40 mph. As soon as I touch the gas, the thing then needs to downshift. This of course happens with any automatic, but it drives me absolutely crazy. So my usage of D4 is for my own comfort and sanity.

I would imagine though, that this downshifting uses more gas than if the transmission just stayed in one gear. Whether you can draw the conclusion that youre actually saving a meaningful amount of gas by using D4 instead of D, I cant say.

mandyfig

D is on overdrive. D4 is without overdrive. Normal operation is D, with Overdrive. Saves you gas. I use the D4 when I need assistannce in slowing down quickly, so as not to burn my pads....

gto406

Would driving in D4 cause any issues with the transmission? When I first got my '04, I didn't have the owners manual, and was driving in D4 (maybe the first 180 miles). I then realized that Overdrive D (was over to the right - should have paid more attention to the shift-indicator on the guages)!

I notice now that that trans accelerates up into D4, then holds that gear around 30 mph (which in Canada is about 50 km/h). It won't shift into D until I am almost at 60 km/h (which is closer to about 40). Is this normal?

Thanks for any info!

The G Man

Driving in D4 wont cause any damage, just waste more gas on the highway.