SaniDel

No, I'm not making this up ... incredulous as I was when I first read it. As documented on page 190 of the GX 460 owners manual the "AI-SHIFT" system automatically selects the optimal gear according to the driver performance and shifting conditions, but only when the shift lever is in the 'D' position.

I'm intrigued by the suggestion made by 'gxgrappler' to leave the shift lever in the 'S' mode, but upshift to '6' so that the transmission is free to use all six gears. However, as the "AI-SHIFT" system is canceled in the 'S' mode, what would we expect this to do for the performance of the vehicle?

What I am hoping for is the shift points to be advanced, i.e., upshifts occur at higher RPM and downshifts occur sooner, i.e., more engine braking, especially when descending downhills. Since mileage in local driving with lots of stops and starts is already poor, I'm hoping this improves drivability ... I'll make up the mileage on long runs at highway speed with the shift lever in the 'D' mode.
Regards,

SaniDel

T4Fun

these gear shift systems are so out of date imho

they need to have NON sequential gear shifting intellgence with this many gears.

Example, instead of going from 6th to 5th gear when you need more speed, how bout jumping to 4th gear instead? One day it will happen. I think toyota may already have this technology.

Koz

Is there a power (snow/power) mode toggle? If there is, the power mode will do exactly what you are looking for.

I know you have the S mode on the trans selector. I use this mode the most on my IS. Just slap it to the left and 4th is selected for highway passing or engine braking. If you need a lower gear just tap it down. This is the best way to have the gear you want for either power or to help shed speed.

Contrary to what some may think the "AI-SHIFT" is a very sophisticated system that learns how you drive and adapts to give the best mileage.

Koz

SaniDel

I believe you, but why is there so little information about this for the GX 460?

I did an exhaustive search of the online GX 460 manuals at Lexus Drivers for the keyword 'shift' and page 190 offers the only explanation of AI-SHIFT! For such a sophisticated system that offers such advantages, wouldn't you think our manuals would say more about it? I suspect the advantages of the AI-SHIFT system were suppressed in deference to achieving higher mileage!

In effect, Lexus is telling us to "leave it in 'D' mode, don't ask any questions and nobody gets hurt"! Granted, there are some details that owners are better off not knowing, but why design and name such a system if there is so little information about its function and its use? I would not be surprised to learn that the same AI-SHIFT system in a different Lexus vehicle designed for a different demographic would provide more useful user information. For example, here is "AI Shift Control" in the RX, which provides more information than we get from our GX manuals:

http://www.lexus.com/models/RX/featu...t_control.html


Here's my take on our options. Leave the shift lever in 'D' mode, try to keep the green ECO lit and the GX 460 will deliver impressive mileage for such a large vehicle, but it will be no fun to drive. It will seem 'clumsy' and hesitant, especially if you need to move quickly to pass or to accelerate from slow speed. On downhill runs it will tend to overspeed, although you can tap the brake pedal and it will automatically downshift.

Or ... move the shift lever to 'S' mode, but keep it in 6 unless you need more engine braking, then push it 'up' into 6 again ... the GX 460 becomes fun to drive rather than a chore although your mileage will suffer.
Regards,

SaniDel

Koz

Technical data/specs has been slowly disappearing. At this point you can't even get any speaker specs including sizes. There used to be a special ML Lexus website that gave all the specs of all the components and a graphic simulation of the car's layout.

I don't understand why all details/specs are not made available in text files from the OEM. They could set it up based on your vin. How better could a car manufacture promote customer satisfaction?

Koz

Capirato

I believe that with my GX 470, the odometer would show 2500 RPM @ 75 MPH.

However, with my GX 460 the odometer shows about 2000 RPM @ 75 MPH.

I just made a trip with the 460 that I had made many times with the 470 and I knew where I had to gas-up. To my surprise, I made it to my destination without stopping for gas.

It is a pleasure to tap the gear shift to the left when passing. The 460 really moves in 4th gear.

~ Cap