Faster Transmission Response
04-17-16, 09:21 PM
#1
Instructor
Thread Starter
Faster Transmission Response
I have a 98 GS4 and a 04 RX330 and one major issue I have with the RX, is the poor downshift response when slowing down, to say 5-10 mph and give it gas, the transmission takes FOREVER to realize I want first gear. If I am giving it 50% throttle at 5-10 mph after slowing and needing to get a move on, the throttle seems like it is there, but the transmission takes an eternity to realize "oh, you want first? hang on while I think about it", then it grabs first and LURCHES forward, giving everyone a very uncomfortable jerk.
My GS however, when down to those speeds is always spot on the right gear. Yeah, I know its comparing a GS to a RX, but wouldn't you think that Lexus would figure that one out?
Is the 04 worse than 05 or 06? Can I use an 05 or 06 trans controller and get some improved transmission response?
You can tell by the lurch, the throttle is responding to the driver's throttle pedal input, but the transmission isn't figuring it out till way too late. I don't get the lurch like at slower speeds and higher throttle input, but it sure makes for a poorly driving car.
I see the same problem when taking slower corners, get it down to 10-20 mph for a corner and the transmission won't downshift till AFTER the apex of the corner, despite what throttle pedal is pressed.
Is this a common complaint?
The GS4 is SOOOO much more graceful in transmission shifting, shift quality and shift timing/rpm. It is so much more refined. GM does 10x better in my BUICK than the RX does.
Needless to say I am getting more and more annoyed with it. I'm just glad it is my wifes car and not my DD, else it would be gone by now.
My GS however, when down to those speeds is always spot on the right gear. Yeah, I know its comparing a GS to a RX, but wouldn't you think that Lexus would figure that one out?
Is the 04 worse than 05 or 06? Can I use an 05 or 06 trans controller and get some improved transmission response?
You can tell by the lurch, the throttle is responding to the driver's throttle pedal input, but the transmission isn't figuring it out till way too late. I don't get the lurch like at slower speeds and higher throttle input, but it sure makes for a poorly driving car.
I see the same problem when taking slower corners, get it down to 10-20 mph for a corner and the transmission won't downshift till AFTER the apex of the corner, despite what throttle pedal is pressed.
Is this a common complaint?
The GS4 is SOOOO much more graceful in transmission shifting, shift quality and shift timing/rpm. It is so much more refined. GM does 10x better in my BUICK than the RX does.
Needless to say I am getting more and more annoyed with it. I'm just glad it is my wifes car and not my DD, else it would be gone by now.
04-17-16, 11:16 PM
#3
Instructor
Thread Starter
04-18-16, 12:49 PM
#4
Lexus Test Driver
The RX may be used to the driving habits of your wife. If you want it to be more responsive and re-learn your habits, reset the ECU by pulling the battery cables for 15 minutes.
There was also a TSB on these for transmission shifting enhancement, you can check to see if that has already been applied to your car.
TSB TC005-03 claims to fix:
There was also a TSB on these for transmission shifting enhancement, you can check to see if that has already been applied to your car.
TSB TC005-03 claims to fix:
Originally Posted by Lexus
To improve the transmission shift feeling during specific operating modes, the Engine Control Module (ECM) (SAE term: Powertrain Control Module/PCM) calibration has been revised. These improvements include:
- Reduced downshift lag when accelerating at speeds from 10 to 20 mph.
- Less gear hunting when driving on/off accelerator pedal at 20 to 30 mph
(for example: during heavy rush-hour traffic).
- Improved response rate during heavy acceleration from a stop.
- Reduced downshift lag when accelerating at speeds from 10 to 20 mph.
- Less gear hunting when driving on/off accelerator pedal at 20 to 30 mph
(for example: during heavy rush-hour traffic).
- Improved response rate during heavy acceleration from a stop.
Last edited by hypervish; 04-18-16 at 12:55 PM. Reason: added details from TSB
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