Is it normal for the car to downshift so much when approaching stop signs, intersections, or going downhill? It isn’t abrupt it just seems like the car won’t coast or freewheel at all. I have the proactive driver assistance off which really accentuated that feeling of slowing down. I need to stay on the accelerator lightly until I am close to stopping. Any suggestions?
Downshift when approaching stops
- Thread starter Trac1
- Start date
I noticed my week old GX would aggressively downshift coming to a stop. But after 1500 miles its adapted some and isnt as abrupt. If it doesnt smooth out I plan on bringing it back to my local dealer to have them reset the transmission to re-learn the adaptations to see if it is smoother.
Wondering if this is partly due to the “small” 6 cylinder and 10 speed trans…. Car wants to be ready for whatever comes next (proactively in power band incase you need to go).
Nah, i've driven my buddy's tundra and it doesnt have this issue.
Mine has started doing this and I'm at 6500 miles. Nothing major, but noticeable.
just unplug the negative terminal on the battery for 30 min. It resets the Transmission ECU. I didn't lose any dash/radio settings when I did this either.
It makes a noticeable difference
It makes a noticeable difference
I received my GX 550 about 4-5 weeks ago. I have not seen/heard/felt my transmission downshift in any manner I could call an issue. Mine must have been programmed differently. I appreciate how folks are putting their issues on the forum - Thanks.
Mine occured after 6,000 miles.
My dealer reset the transmission computer and it seems to have gone away. The catch is that he said they all do this eventually and that this is only a temporary fix. If mine comes back, I’ll try the battery disconnect idea before going back to the dealer.
Have you all tried changing the trailer brake controller settings? I noticed when I got my car that one of the Trailer brake types was on by default. I turned it to “TBC off” since I don’t regularly pull a trailer (and certainly not one with brakes). Just curious if these settings might also impact the way the car downshifts.? Just a theory. FWIW I haven’t noticed any unusual downshifts, but also only have 2200 miles. This is under Settings -> Vehicle Customize -> Utility -> Brake Type
Do you have any more info on this? I haven't seen anything like this in all the menus and sub-menus.
The automatic downshifts are way too aggressive, in my opinion. You'd think at least in Eco mode the vehicle designers and programmers would let the truck coast along in a high gear instead of aggressively downshifting. I'd love to see Lexus or the aftermarket offer a re-mapped Eco mode where you could coast along in 10th gear in Eco mode instead of the damn thing constantly engine/transmission braking as you coast and your speed naturally decreases due to all the friction variables.
Mine was set to 0-4999 (1st setting) from factory. No difference in braking with it set to TBC Off that I could discern
Funny, I actually like the way the transmission tries to hold your driving speed with a couple of downshifts to give it a bit of compression breaking, maintain speed and not make you ride the brakes as much. On a steep decline the truck will eventually overcome the slight compression breaking and then almost speed up as the rev's kick in. This may have something to do with the turbos spooling up. I think it is nice and hope they don't "fix" this. I find it quite annoying when you don't get some engine breaking.
I’ll check it out tomorrow and let you know.
I agree, but I think ECO mode should let you coast free. If you knowingly choose Eco mode then you know what you’re getting into!
Agree on the ECO mode, that seems a reasonable request. I have tried to up shift with the paddles a couple times when coasting to get into a higher gear but it did not seem to allow the forced override.
Now that I'm thinking about that, I recall setting the TPS in my old 4Runner (1985) and read that if the truck was compression breaking it cut fuel, but at idle it did not.
So, maybe the GX is cutting fuel during this compression breaking to be efficient, AND keeping you from speeding down a hill with gravity. Kind of like how that driver monitor is helping keep us all in line and paying attention.
Now that I'm thinking about that, I recall setting the TPS in my old 4Runner (1985) and read that if the truck was compression breaking it cut fuel, but at idle it did not.
So, maybe the GX is cutting fuel during this compression breaking to be efficient, AND keeping you from speeding down a hill with gravity. Kind of like how that driver monitor is helping keep us all in line and paying attention.
That would be great if it is indeed cutting fuel, but I still want to free-coast in Eco mode. I hate when I accelerate after a full stop and then suddenly a light turns yellow and you have to get off the gas an stomp on the brakes. I feel like I'm committing a crime against the universe for wasting all that energy. I get nearly the same feeling when I'm coasting along and and the truck starts downshifting and consuming that energy I dedicated to acceleration or maintaining a steady speed. Maybe I just need to see a therapist.
Lexus maybe never adopted the old Toyota slogan that it could go fast down hill with a tailwind.
Hope you enjoyed today's session.
On a positive note, I did just hear from an Overland Expo in CA, that Slee drove both a modified LC250 and modified GX 550 across the mountains (Denver to CA) and got 13.4mpg in the LC and 13.9 mpg in the GX! Hope that helps offset you crime to the environment between stop lights.
I just don't drive it hard unless I fully expect the MPG trip tracker to be low.
Hope you enjoyed today's session.
On a positive note, I did just hear from an Overland Expo in CA, that Slee drove both a modified LC250 and modified GX 550 across the mountains (Denver to CA) and got 13.4mpg in the LC and 13.9 mpg in the GX! Hope that helps offset you crime to the environment between stop lights.
I just don't drive it hard unless I fully expect the MPG trip tracker to be low.
GX550 Forum Photos
GX550 Forum Photos
