4GS Achilles Heel - The Tranny
#17
In Sport + mode, the car does hold the gears when you press down and immediately release the pedal. Nothing to do with the tranny problem here. I have no issues on my GS. It feels alot better than the 7 speed on my BMW 5 series and 8 speed on my Audi A8.
#18
This happens in all modes. It might need a reprogram, but we'll see.
As for the "anything more than 6" comments, yes, that's what was said each time about the next number of gears. The flaw in a lot of the comments here about "oh, then it will just keep shifting a lot and hunting with even more options to choose from" is that hunting isn't about the number of gears per se. It's about a poorly programmed TCM that can't find the right gear, so it keeps shifting around. You have to remember what "hunting" means. It doesn't mean shifting. It means shifting back and forth with potentially long gaps between shifts as it can't find the appropriate mathematical answer for the equation that tells it what gear to choose.
More gears means the gears are better matched to each situation. More gears means it doesn't have to hunt. for the right one constantly because it can just shift to the appropriate one since shorter distances between gear ratios means you're more likely to have a match for a given situation.
My last car was a Toyota and didn't do this. It had a CVT, though (Highlander Hybrid), but the gas Highlander I had before that didn't do it either, and it was also a 6AT. I'm pretty sure this can be improved with better programming, but it would also be helped by an 8AT IF and only if the 8 is a good one (per the point on the 8AT in the LS460).
As for the "anything more than 6" comments, yes, that's what was said each time about the next number of gears. The flaw in a lot of the comments here about "oh, then it will just keep shifting a lot and hunting with even more options to choose from" is that hunting isn't about the number of gears per se. It's about a poorly programmed TCM that can't find the right gear, so it keeps shifting around. You have to remember what "hunting" means. It doesn't mean shifting. It means shifting back and forth with potentially long gaps between shifts as it can't find the appropriate mathematical answer for the equation that tells it what gear to choose.
More gears means the gears are better matched to each situation. More gears means it doesn't have to hunt. for the right one constantly because it can just shift to the appropriate one since shorter distances between gear ratios means you're more likely to have a match for a given situation.
My last car was a Toyota and didn't do this. It had a CVT, though (Highlander Hybrid), but the gas Highlander I had before that didn't do it either, and it was also a 6AT. I'm pretty sure this can be improved with better programming, but it would also be helped by an 8AT IF and only if the 8 is a good one (per the point on the 8AT in the LS460).
#19
I wonder if your issue is more getting used to the conventional transmission after being used to the CVT than any issue with your unit.
I hate CVTs, but my wife was very used to the CVT in her Prius and it was a lot of adjustment for her to get used to a conventional auto again when we traded it.
I hate CVTs, but my wife was very used to the CVT in her Prius and it was a lot of adjustment for her to get used to a conventional auto again when we traded it.
#20
Steve, that's a great point, and one I wondered about myself until that situation where the RPM were pulsing back and forth while in cruise control. I also just drove my wife's RX for 6 hours over 2 days on the highway, and didn't find the same situation.
Yeah, definitely a bit of CVT adjustment (like I went through when I stopped driving turbo engines after years of doing it), but I think there's more to it than that.
Yeah, definitely a bit of CVT adjustment (like I went through when I stopped driving turbo engines after years of doing it), but I think there's more to it than that.
#21
In Sport + mode, the trans does stay revved up when you accelerate and immediately release the pedal. I've seen it hang at 4,500 rpm for more than 5 seconds until normalizing. Some background on me - I worked in the business and discussed this with a service guy (friend that I worked with previously) who then went to ask the techs. All the techs agreed this was normal operation...unfortunately there's nothing to fix or adjust. They had heard it from other customers too.
I dislike the behavior, but, I guess it's something I'll need to deal with. For me, this ONLY happens in Sport mode.
I dislike the behavior, but, I guess it's something I'll need to deal with. For me, this ONLY happens in Sport mode.
#22
That holding w/ a high rev def happened to me in Sport S+ mode the other day (should be the same as putting it in Sport in this case). It's actually a really bad programming since it makes the engine less responsive and working harder.
I needed to pass in an emergency situation, revved, and then the situation changed drastically, so I came off the gas, but the engine kept revving. Then I needed power again, and it just couldn't deliver despite sounding like it was given the high revs.
I needed to pass in an emergency situation, revved, and then the situation changed drastically, so I came off the gas, but the engine kept revving. Then I needed power again, and it just couldn't deliver despite sounding like it was given the high revs.
#25
An update - the issue happened the other day and when it did, the trans held, revving at about 5,000 RPM. When this happens, it make the vehicle almost un-drivable. There's no way to accelerate until the the trans normalizes and downshifts. This is the same behavior as bdizfiz experienced. Frankly, it's unsafe. I've resigned myself to drive in normal mode until such a time that Lexus acknowledges the issue and does something to remedy it.
It's really disappointing as I love just about every other aspect of the vehicle.
It's really disappointing as I love just about every other aspect of the vehicle.
#26
I had a large transmission surge about a week ago when maneuvering in very heavy traffic on the freeway, It suddenly surged up to around 5000 RPM and stayed there. In my case, the cause was driver-induced when I accidentally hit the left shift paddle on the steering wheel. When I realized what I had done, I held the right paddle down to put the car back in Drive. I'm not saying this is what others have experienced. I just saying it happened to me and it surprised me.
#27
Regarding the "need" for an 8-speed transmission in the GS, I was reading about the newly designed 2014 Stingray Corvette in the May issue of Car and Driver. The car has a 450 HP engine that puts out 450 LBS of torque. The car comes with a 6-speed automatic transmission. An 8-speed in the GS350 will be a great sales gimmick but likely won't add much in the way of performance or fuel efficiency. It will certainly add to the cost of the vehicle.
#28
Regarding the "need" for an 8-speed transmission in the GS, I was reading about the newly designed 2014 Stingray Corvette in the May issue of Car and Driver. The car has a 450 HP engine that puts out 450 LBS of torque. The car comes with a 6-speed automatic transmission. An 8-speed in the GS350 will be a great sales gimmick but likely won't add much in the way of performance or fuel efficiency. It will certainly add to the cost of the vehicle.
#29
Regarding the "need" for an 8-speed transmission in the GS, I was reading about the newly designed 2014 Stingray Corvette in the May issue of Car and Driver. The car has a 450 HP engine that puts out 450 LBS of torque. The car comes with a 6-speed automatic transmission. An 8-speed in the GS350 will be a great sales gimmick but likely won't add much in the way of performance or fuel efficiency. It will certainly add to the cost of the vehicle.
#30
Regarding the "need" for an 8-speed transmission in the GS, I was reading about the newly designed 2014 Stingray Corvette in the May issue of Car and Driver. The car has a 450 HP engine that puts out 450 LBS of torque. The car comes with a 6-speed automatic transmission. An 8-speed in the GS350 will be a great sales gimmick but likely won't add much in the way of performance or fuel efficiency. It will certainly add to the cost of the vehicle.
Last edited by BarrettF77; 04-01-13 at 11:25 AM.