Mine has also never exhibited a problem like this, I'm at 19k miles, almost all of it very heavy duty.

 

mine never has done this. good luck with those problems! wonder if they would replace the transmission?

 

That's exactly it; now that I think about it temperature could be an important factor, all of the recent times my car has done this have been during the first few minutes after a cold start.

This obviously seems to be more than a one-off issue. What I'd like to know is whether this is

a) normal behavior that is triggered by a rare combination of factors (cold, pedal position, speed, etc).

b) software glitch (trans cal bug that they didn't catch in development)

c) hardware problem (sticky valve, as some have speculated above)

I doubt a) is right, at least I have a hard time believing the development engineers coded this behavior on purpose because it results in very poor driveability. That leads to b) or c) and I'm leaning towards b).

Unfortunately this is one of those behaviors that is impossible to replicate on demand, but if it's happening to a large proportion of posters here there's a good chance Lexus is aware of it. If enough owners complain it could filter up and back down as a service bulletin. I'll definitely mention it the next time my car goes in.

 

I know what you guys are talking about. Some of you sound like you have never driven a automatic performance car before...

1. You accelerate hard.
2. It's in D.
3. The car does not upshift for a few seconds and stays in gear.
4. Sport mode (?) (I'm usually in sport mode so not sure if it happens in normal mode)

I'm sorry but this is actually NOT a problem, but a software feature. Like some have mentioned, the shift software has a predictive nature to it, so it will delay upshifts if it senses aggressive driving, just like it will shift at higher points if you have a lead foot. I was actually very impressed when it happened to me the first few times, because I was on the freeway and trying to maneuver across multiple lanes during a merge. So the car stayed in a lower gear and allowed me to stay in the optimal power band even in D, until I got to where I want to go, then it upshifted. If you keep the gas down, it will upshift when it nears redline. How the car behaves depends on your throttle control during this time.

Yes, like all software there are edge cases where it predicts incorrectly. There was a couple of times when I actually didn't need it to stay in gear that long, but it was still useful regardless. Nothing wrong with being in the power band when you're trying to get somewhere quick!

</Thead>

 

I hear what you're saying, but this is more than an 'edge' case so it's either a malfunction or just poor calibration. And no, this is not in Sport mode (where I agree with you this behavior would be more consistent).

Throttle position at 1/2 (or less) and lifting to idle seems to be a pretty clear condition for an upshift - but it doesn't. I've basically had the throttle feathered with the momentum of the car keeping the revs above 4k, and it still won't shift for a good 5 seconds.

p.s. I had to laugh when you say it sounds like people haven't driven an automatic performance car before... IMO there wasn't one on the road before the ISF

 

I have had this happen to me once or twice. Once to my grandson when he was driving my car with his father.

I think that it has something to do with the manual/automatic gate on the shifter because if you shift it over to manual and then back to automatic it seems to go ahead and shift normally.

Pat

 

I don't mean to disrespect you but you have not experienced what we are talking about and you have no idea what it is that you are talking about here.

This is NOT a feature of a high performance transmission. I am well aware of the transmission holding gears in sport mode, this is not that. This is occurring at moderate throttle positions in normal mode, only in 2nd gear and only when cold. It is not predictable and not reproduceable.

Never driven an automatic performance car? Does a Porsche 996 twin turbo tiptronic count?

 

I tend to agree, when this happened to me, I though it was a feature of the sport mode to keep me in the higher band of the RPMs, keep you foot down and it will up-shift around 6k, lift off your foot off the throttle and it will stay on the gear for few seconds before down-shiftting. Appropriate behavior for a smart sport mode.
Only in Sport mode, and temperature seems to have no impact on it.

 

I have experienced this only when I start the car first time in the morning and it is very cold. once it heats up...no problemo

 

A few people have reported this exact same issue, and I've experienced as well, but only once. Trans was in "D" mode too.

Thread here:

http://www.lexusfforum.com/forums/showthread.php?t=1177

 

Correct me if I'm wrong, but if you are saying that you lifted the throttle to 1/2 or less AFTER the car is holding gear at revs above 4k, then the car may not upshift immediately until it "senses" that you no longer need it to hold gear. 5 sec seems long though, and again it probably depends on what else you are doing (braking, turning, etc).

Touche!

If you are just driving conservatively and the car doesn't shift, then that's a different problem than what the OP described, and that has never happend to me. The OP clearly said he was driving aggressively in D, which is the problem I addressed.

Apparently not if you drive conservatively, no.

 

I know this 'feature' in Sport mode and understand why it would behave that way. But, what we're talking about is NOT happening in Sport and occurs even during very light driving.

 

thanks for the quick response everyone. looks like no one has a fix yet. i will see what my service manager has to say.

 

Thats quite normal....this happens if you go WOt or in between shifts for me when I get of throttle while the car is high reving and in the throttle hard....it happened with previous vehicles not as noticable prob bc...one less power and less gears evening out the gear response than the F, also when sport or manual is ingaged the torque converter reverts to being "always locked" unlike most cars that do not do this that is why when in sport or in the gas hard the F direct shift is very hard and precise...thus causes a hard "hanging up" feeling thus as driver give a little gas to smoothen out the throttle and or go to M back to D quickly just a part of driving a performance natured vehicle....hey try driving an M6 with SMG or a 599xx driven my friedn Jonathans a few time and I can never seem to "heel-toe" quick enough before the ferrari shifts ..

 

You couldn't say it better, this is what's happening. I've experienced this issue many times since I got my car in June 2008, and it only happens in situations like the one explained by dkaplan435. This topic has been covered before in here.