Can someone explain to me why the AWD Lock Mode feature is not available on RX450h? I saw a Lexus video introducing the feature but on my 450h, in that console location (right below the Eco/Normal/Sport drive mode dial) I am instead seeing a EV Mode button.

Is it because 450h is hybrid? But then isn't it true that even for hybrids one may need to send torque to the rear wheels in certain situations? Thanks in advance for explaining.

 

It is because its a hybrid, the 450h is front wheel drive with the exception of the rear wheels are powered by a electric motor, from 0mph it powers the rear wheels till mid 20mph if im not mistaken. The diff lock or "awd lock" on regular f sports or awd models have a drive train that connect the front and back wheels that have their own differentials connecting to the transfer case through drive shafts or other wise known as the drive train.

But generally the lock on awd gas models are only to 25 mph for safety reasons, then it unlocks the diffs if my memory serves me right, so its essentially the same thing, But on the 450h software makes the rear wheels sometime act unpredictably. But from videos ive seen all rx's are generally front wheel biased, they do send some tq to the rear wheels but its def not more than 30% rx350 or 450h. Having said that I drive in 1.5 feet snow in the winter and plow through fine with the awd lock button pushed or not, having skinny tires (235's) and a decent amount of weight make it nearly impossible to get stuck with even the poorest of awd systems. Even those that are heavily fwd biased like lexus suvs.


It woulda been cool if they did a regular rx350 awd with a diff lock and see if you get similar results. But from driving I can tell you its VERY fwd biased with the awd lock pushed or not, regardless of the little display on the dash shows you 50% of the power is going to the rear wheels.

 

Wow thanks for the nice explanation. Better than I could Google.

 

I live in the Colorado mountains and have a Lexus and a Rav, which are both hybrids. Neither one of them is an off road vehicle, but do great in deep snow. Only a couple of times have I had to turn off the Traction Control in order to force power to the front and back. They both do very well in normal operation. I can think of no time when a locked system would be of much value, since the vehicles do great on normal roads.- plowed or unplowed.

 

Good tips! I'll keep that in mind and disable Traction Control when needed. I don't do off road but dealing with deep snow is not up to me.

 

The AWD lock button on the gas versions lets you avoid any loss of momentum
it you are driving in slippery conditions. Possible that the automatic engagement
triggered by the Front Wheels slipping might occur too late and the vehicle might
stop moving. Stab the button and as previously stated you're AWD up to 20 mph.

The AWD programming of the Hybrid is much more linear, adding power gradually.
Did you realize when you are reversing in a Hybrid that it is All electric drive? IC motor
is running and powering they system but the Synergy Drive doesn't have a reverse...

 

Yes I do realize it. When I reverse I'm getting a terribly loud squeal noise that resembles an aging engine belt that badly needs replacement. Dealer told me the 450h is designed that way due to new regulation (introduced this or last year?) that requires electric vehicles to alert pedestrians when reversing (or driving forward at low speed).

It's embarrassing though as every time I pull out from my garage neighbors may conclude that engine belt problems start developing on new Lexus vehicles these days.

 

Oo yikes that sounds annoying. Im sure there's a way to snip a wire and stop the sound, recently had a friend do it on his 2015 Tacoma because of the crazy embarrassing 1990's reverse music that plays lol

 

Agreed! My neighbor has occasionally given me a “wth is wrong w/ your car” look when backing out of the garage and driveway. That noise is so awful reverberating around the garage!

 

strange, my 450 doesn't have any crazy loud sequel sound in reverse that sounds like belts slipping,

 

My 2018 450HL has no sound when in reverse, and neither does the Rav H.

 

More of a "blowing over an empty bottle" type of sound. When there is no
IC motor sound and the hybrid is moving slowly the sound ebbs and surges.
Loudest when you first release the brakes and move electrically, lessens once moving.

 

JSracer, golferjack, given your 2017 & 2018 RX450h don't have the noise, my dealership must be telling me the truth then, that Lexus only introduced the embarrassing noise in 2020 (my model year) or the year before. (Any 2019 RX450h owners can confirm if they have the noise?)

Turns out our sister (or parent) company Toyota is doing the same to their 2020 hybrids. My RX sounds exactly the same as in this video, especially towards the end @00:10, only much louder than suggested by the video.

 

I'm willing to pay Lexus to replace the "noise generator" on my 450h with a 1980s 3-tone reverse melody... at least people won't wonder if I'm driving around on a Lemon Lexus.

 

I wonder why it is different than the normal sound when going forward, which is a sound mandated by the gov't.