Gearbox hesitation

[sevoflurane]

Hi Guys!

I just wanted to run something past UK owners of lexus F products. I got my RC-F a year or so ago, it's bone dry stock and I am loving it! The build quality is incredible, the engine is brilliant and the car does everything I'd ever want it to do

I only had one issue that has been bugging me this whole time - the fact that when I'm pootling at 30ish mph and want to speed up in normal (or even sports) mode, and the car bogs down in RPM and takes about 2 seconds to drop from 6th to 2nd gear to give me the power I want - the power isn't lacking but the delay means if I want to do a quick overtake I lose my window of time!

Looking online, some americans have got their ECUs flashed. Others say its the adaptive transmission learning behaviour and it gets better when I pull the Battery (or fuses to reset the ECU). I wanted to know if UK peeps were having this issue, and how we sorted it? It's quite disconcerting especially as I haven't seen this issue in other cars that I've driven lately, including other performance cars, and this delay ironically makes it a less good daily (as it is never an issue when I am hooning the car in manual mode...)

Some great resources on this forum though! I am gonna try and get android auto / carplay retrofitted onto my car soon. I also need to book in for my vent tube recall!

If anyone has an F and is near Greater Manchester... drop me a message!

Thanks!

[RadicalCoupe-Fuji]

Ive not had mine long & ive only really had cars with manual gearboxes my whole driving life, so its not coming naturally to me, but when I know im going to want it to do something I manually knock it down a few gears with the paddle & then speed up rather than wait for it to read my mind or change it to sport+ mode.

[4969_LXS]

ISF owner here. Are you pressing the accelerator pedal all the way down so it clicks the kickdown button ?

[Rob RCF]

It seems to be just one of the flaws of the car. If you come out of anything more modern, especially a dual clutch, the gearbox does feel horrendously slow at times. The gear ratios are also too long, but that's another matter.

I think the worst thing is that occasionally the transmission does get it right, I've had it go from 7th > 2nd pretty instantly on several occasions (which is amazing). Try driving along at 40-45 until the trans is sitting in 7th, then nail the throttle and see what happens. For me this even worked in normal mode. The trans takes a while to fully warm up as well, so don't assume that just because the engine is fully warm that the trans is also.

I'm not quite sure why it sometimes works, once was right after a transmission fluid change and I believe the Battery was also disconnected as it was in for a major service, so ECU would be reset. If you do decide to pull the fuse to reset the ECU, just note that it will put you on a base map and the car might feel a bit slow for a few days/weeks until you've built up the knock tables (search KCLV for more info). You can speed up this process somewhat by doing in-gear pulls, but I find it just takes time and consistently running it on good fuel (super unleaded).

[Jgtcracer]

11 hours ago, sevoflurane said:

Hi Guys!

I just wanted to run something past UK owners of lexus F products. I got my RC-F a year or so ago, it's bone dry stock and I am loving it! The build quality is incredible, the engine is brilliant and the car does everything I'd ever want it to do

I only had one issue that has been bugging me this whole time - the fact that when I'm pootling at 30ish mph and want to speed up in normal (or even sports) mode, and the car bogs down in RPM and takes about 2 seconds to drop from 6th to 2nd gear to give me the power I want - the power isn't lacking but the delay means if I want to do a quick overtake I lose my window of time!

Looking online, some americans have got their ECUs flashed. Others say its the adaptive transmission learning behaviour and it gets better when I pull the battery (or fuses to reset the ECU). I wanted to know if UK peeps were having this issue, and how we sorted it? It's quite disconcerting especially as I haven't seen this issue in other cars that I've driven lately, including other performance cars, and this delay ironically makes it a less good daily (as it is never an issue when I am hooning the car in manual mode...)

Some great resources on this forum though! I am gonna try and get android auto / carplay retrofitted onto my car soon. I also need to book in for my vent tube recall!

If anyone has an F and is near Greater Manchester... drop me a message!

Thanks!

What’s the mileage?  Will it have had a fluid change before?

[08ISF]

My GSF used to do the same thing. I think it's a feature of the gearbox. Some testers described it as "dimwitted". It was always a bit of a disappointment as the car never felt as lively as it should and you needed to get some revs on to get the best out of it.

It might also be something to do with the self learning feature of the gearbox. When you live in an area  with a 20mph limit the gearbox could be forgiven for going to sleep.

[sevoflurane]

Thanks for all your input team! I think I'll try to reset the fuses and see how it goes - I start with a much larger commute tomorrow (30 miles each way mainly motorway) so that'll give me a chance to reset the ecu and do some good in gear pulls...

The car is 36,000 odd miles (10k of which are mine) - it has been serviced by Lexus main dealers in all its history but I don't know about whether it has or hasn't had a fluid change. It's a shame because my old car was a 3 litre supercharged jaguar with a ZF 8 speed and that was much keener to downshift at the drop of a hat and take off than this despite being physically much slower! Getting it to kickdown hard seems to be the way but many of the times it happens is when the car is lugging on a hill and I want it to speed up a little but it takes forever for it to do so ! 

Then again, I only pour in petrol and it goes no questions asked and is super reliable, so it's hard to complain! 

Do you guys know if Lexus main dealers will take objection to giving me the yearly manufacturer warranty if I get an aftermarket exhaust or upgrade the infotainment to an android auto head unit?

[hockeyedwards]

43 minutes ago, sevoflurane said:

Do you guys know if Lexus main dealers will take objection to giving me the yearly manufacturer warranty if I get an aftermarket exhaust or upgrade the infotainment to an android auto head unit?

As long as any problems, should they ever arise not be attributed to the aftermarket parts, you'll be fine.

i.e if you have a brake failure, that most likely wouldn't be caused by an aftermarket headunit! 😛

[BTCC_ Racer]

Hi there,

 

A gearbox flush and ECU reset will certainly help. It worked for my ISF however my box ran great if anything the flush and reset just made it that little bit better.

[DAW]

I always use the paddles to drop a couple of gears, in whatever drive mode I’m in, to increase my speed for an overtake or going up steep hills etc like I would in a manual car. I haven’t ever relied on the car to kick down as I prefer to be in direct control of the acceleration.  Works as well in the Lexus as it did in any of my previous tiptronic autos and it often changes down just as I’m about to on hills far better than any of my previous autos did.  
Can’t say I have ever noticed any issue with lag TBH other than the throttle retardation in eco.

[Jgtcracer]

10 hours ago, sevoflurane said:

Thanks for all your input team! I think I'll try to reset the fuses and see how it goes - I start with a much larger commute tomorrow (30 miles each way mainly motorway) so that'll give me a chance to reset the ecu and do some good in gear pulls...

The car is 36,000 odd miles (10k of which are mine) - it has been serviced by Lexus main dealers in all its history but I don't know about whether it has or hasn't had a fluid change. It's a shame because my old car was a 3 litre supercharged jaguar with a ZF 8 speed and that was much keener to downshift at the drop of a hat and take off than this despite being physically much slower! Getting it to kickdown hard seems to be the way but many of the times it happens is when the car is lugging on a hill and I want it to speed up a little but it takes forever for it to do so ! 

Then again, I only pour in petrol and it goes no questions asked and is super reliable, so it's hard to complain! 

Do you guys know if Lexus main dealers will take objection to giving me the yearly manufacturer warranty if I get an aftermarket exhaust or upgrade the infotainment to an android auto head unit?

I’ve got both and have no issues with the warranty.  Can imagine if I tried to claim an infotainment/exhaust issue they would moan mind you.  Don’t actually think the infotainment is covered anyway!

[MNMJ]

On 1/30/2023 at 10:21 PM, 4969_LXS said:

ISF owner here. Are you pressing the accelerator pedal all the way down so it clicks the kickdown button ?

It took me a while to discover that there is something beyond what feels like the end of the throttle travel. Acceleration is great anyway, but if you go to the floor you get something I believe is called Wide Open Throttle and  a kickdown to the lowest gear. It was certainly a WOT !!!!!! moment when I first tried it

Only try it on a straight dry road

[hondansxr]

have you tried a pedal controller , i purchased one for my rc h 300 and was blown away by the trottle responce (in race mode ) so much so i bought one for my sc430

[hondansxr]

pedal pro by tunit .

[rsmallwo6]

Another UK spec car, I get a hesitation when it's dropping down into 4th specifically. None of the other gears do it, it's fine in manual mode dropping to 4th. But in normal auto it seem to have a brain fart when going for 4th. It applies an initial blip of power then pulls back, has a quick think and then goes "oh yes, this is the gear I wanted" and carries on as normal. I doubt it does this in sport or sport+, but when your just tootling about you just want normal mode.

[RadicalCoupe-Fuji]

Ive always had manual cars & avoided autos, rcf only comes in auto like a lot of similar cars, i found it hard to get used to, go to overtake & nothing happens, but now I am used to manually dropping gears with the paddles when I know I'm going for an overtake or something & the car takes off when I want rather than ending up steering into the right lane but not going anywhere. Auto box can't read your mind & in normal or eco the gearbox is also fast asleep.

[BillNick]

Sport and Manual mode if you want to be in full control all the time.

[Pielight]

Like some have mentioned, it's best to use the paddles to downshift, clicking 2 or even 3 times rather than waiting for the transmission to realise your intention - this gets the car ready for action much quicker.

You have to keep in mind that after doing this, the transmission will not shift up (even in auto) and will just stick at the rev limiter without changing up - not good if you need to keep accelerating! By changing up manually, you effectively put the transmission into manual and it only reverts to auto when it is forced to down shift when decelerating.

 

 

[Duggie B]

Or hold the up shift paddle and 'box will revert to auto...

[MNMJ]

Or leave it in the same gear for a while, and it will revert to auto.

I can't quantify the 'for a while', but I would like it to be longer

[ColinBarber]

1 hour ago, MNMJ said:

I can't quantify the 'for a while', but I would like it to be longer

30s apparently:

 

When the shift lever is in D, the driver can momentarily select a desired shift range by operating the shift paddle switch (transmission shift switch assembly). Automatic shifting will be reinstated under the following conditions:
- The vehicle has stopped.
- The driver continues to push the shift paddle switch (transmission shift switch assembly) in the "+" direction longer than 1 second.
- The driver continues to depress the accelerator pedal longer than 30 seconds.

[Pielight]

On 1/30/2023 at 10:21 PM, 4969_LXS said:

ISF owner here. Are you pressing the accelerator pedal all the way down so it clicks the kickdown button ?

In the 3.5 years I've owned my GSF, I've always used paddles in my GSF and never tried this (using full throttle kickdown)......until yesterday day that is. It literally changed down in an instant and took off like a scalded cat! No hesitation at all and with the ideal gear for max acceleration selected, i.e. gear with RPM that felt right at peak torque. And that was just in normal mode...well impressed!

Although it will probably not be something I use that frequently (once Ive had a good play in sport and sport+!), being aware of this capability to use as required is of great value 

Pleased I read your post! 👍🏼

[BillNick]

Ha I guess this is one of the downfalls buying a car 2nd hand you don’t really get a decent handover of all the functions.

Having said that I discovered the kickdown on my test drive, a proper gut wrencher lol 👍🏼

[rsmallwo6]

59 minutes ago, BillNick said:

Ha I guess this is one of the downfalls buying a car 2nd hand you don’t really get a decent handover of all the functions.

Having said that I discovered the kickdown on my test drive, a proper gut wrencher lol 👍🏼

So as a fellow UK spec car owner you don't experience this same hesitation when dropping to 4th in Normal mode? I'll try it in Sport a few times to see if it helps.

[BillNick]

I find the box sluggish and unresponsive in Normal mode in general, I haven't really pin pointed it to a particular gear change.

If I want responsive I immediately turn the dial to Sport and think nothing more of it.

You have to remember the ECU is trying to balance economy when in ECO or Normal, so it will be applying that to gear changes etc.

Sport and Sport + there is not Economy mapping on either the box or the throttle.