Seppo

I have never been a fan of automatic transmissions in general, owned nothing but stick shifts for decades and nearly a million miles of driving. These days you have to accept automatic once you get beyond a very limited slice of the market, and my 2014 GS350 AWD is only my second automatic for my own cars. I would rate it a typical automatic, not impressed.

My previous BMW, and my better half's Audi, had the ZF eight speed auto, generally considered one of the best ever. I never had a complaint about that transmission in either vehicle: step-off was crisp and sure, shifts fast and smooth, responsive manual shifting, lots of ratios, both cars returned excellent fuel economy for their class. Passing on a two-lane is a snap, with immediate and unobtrusive shifts to appropriate gears.

I find step-off to be inconsistent in this Lexus six speed, sometimes it jumps off the line with the slightest throttle, most of the time there is an annoying delay until it spools up and the car moves out. It encourages a sedate driving style to remain smooth.

Having to pass on a two lane, or even being balked by someone slowing in the left lane on an uphill, results in several abrupt shifts and a sudden engine caterwauling, not a confident and responsive feeling like the BMW and Audi with the ZF, or my buddy's Jeep Grand Cherokee with the same transmission but worse power to weight ratio. Yes, I can anticipate an overtaking move and switch to Sport setting or do a manual shift, but it is never as smooth as the equivalent in those ZF 8 vehicles.

My biggest gripe was using manual mode last week, descending a steep mountain in a line of slow-moving traffic during a heavy snowfall. The Lexus transmission did not behave at all like a manual in that circumstance, holding M2 with a very steady throttle in these slippery conditions resulted in a lot of drivetrain lash, with the tachometer showing surging up and down with the RPMs. My passenger was alarmed, "what the heck are you doing, we're going to lose control!". It felt as if I were applying throttle, then lifting, then applying again, although I was either completely steady or even foot off the accelerator. Most annoying and useless, when I wanted the benefit of some engine braking to keep us at a steady descent in awful conditions.

So back into D, and things smoothed down, but now I had to ride the brakes to keep us descending at the rate of the other traffic. I don't get why the manual mode does not simply lock the gear under normal throttle control.

Anyhow, this Lexus six speed auto is a pretty mediocre box that can't compare to the better autos on the market today, especially the ZF8 and the VW DSG or Porsche PDK dual clutch type transmissions. It is what it is, but makes me yearn for a good manual or at least another ZF8.

er34

Did you put the gear shift lever in M? Or did you simply use paddles to put it down to M2?

What was your speed and rpm? I get that you were trying to use engine braking but if you are in 4-5k rpm in 2nd gear, you are bound to lurch forwards if you give it throttle because you are in the powerband.

Seppo

I moved the gear selector to manual, and downshifted to M2 as shown on the instrument display. We were doing maybe 25 to 30 mph on a steep, slick downhill, RPMs were below 4,000, mostly around 3,400. I never experienced that surging in any other car when in manual mode, it did so even when I had fully lifted. It was like an exaggerated version of the surging cruise control in hilly terrain. Only returning to the Drive mode relieved it. Seems to me selecting Manual should feel much more like a clutched car, as it does in the ZF8. I left the drive mode in Normal, did not switch to Sport mode, maybe that would have made a difference. In my car, the paddle shifters only work in Sport mode, I was using the +/- shift lever mode.

I get it that there are no perfect vehicles, just making the point that the auto transmission behavior in this car is far from the current state of the art. Nothing more than the header indicates, disappointed with the transmission performance.

bclexus

You must have a one-off car...

JDR76

Luckily I have not experienced anything off with my automatic. I find it odd that your paddle shifters don't work unless you are in Sport mode. In mine they work in all four modes. Something else may be going on.

Seppo

As my car is equipped, I have only three modes: Eco, Normal, and Sport, no Sport+ in my car. The owners manual says for this equipment level the paddles work only in Sport or Manual mode, and they do nothing when in Eco or Normal. I was in Manual, but used the shift lever instead of the paddles.

bclexus

My paddles work in all modes. I strongly suspect yours do too! Have you tried to use the paddles in ECO and Normal modes? I've never heard of any vehicle that has shifter paddles in which they cannot be used except when in a specific drive mode.

Can you say what page in the Owners Manual it says the paddles work only in Sport or Manual mode, and they do nothing in ECO or Normal mode?

e60bmw

iTrader: (1)

You might be able to have it "relearn" the shift points. I think removing the battery will do that, maybe theres another method like the BMW's used to do by holding the pedal down for x amount of time. If you want to wake up the car with shifting and responsiveness add a apexi accel. It removes all delay, I have instant throttle response with it, I have a 13 awd too. Its adjustable on the fly with 8 modes, it was the first mod I did on my GS.

Superman60

Wow! I've never experienced any of these symptoms in my 2014 GS350 non-F AWD. Maybe you should take it to the dealer and have them check it out.

MustangSal

Sell it.

101010

bclexus

Seppo - Did you ever figure out whether your shift paddles work in every drive mode, or not?

highrev6

SpicedRum

Still a new owner of an '18 AWD and haven't encountered the conditions you faced. But, I know what you're talking about when you talk about abrupt on/off power when downshifting in other cars/SUV's over the years in snow, and off-road as well.

It doesn't sound like the transmission was doing anything unusual though...could be wrong. Indeed there may be an issue here. However, the engine was at a point where it's making very strong power and the on/off throttle transitions would be more pronounced. The engine tuning may be a little "off" during this transitions which could exacerbate it. And it's very easy to over-modulate the pedal too suddenly when your brain, foot and car dynamics have to interact in untested and stressful situations. I've had many machines (motorcycles especially) that are very sensitive with small throttle movements at high rpms, GS could be like this as well.

Next time use a gear higher and rely more on brakes rather than throttle to control as well as being as smooth as possible, anticipating your throttle/braking needs as far advance as possible.

Just for discussion sake, my 2018 GS350 F Sport AWD will shift anytime the paddle shifters are used. While I haven't tested all the sport and Sport + modes, it looks like if the gear select lever is not in manual mode the paddle shifts will default back to automatic mode after a short time. Meaning if you downshift it will do it, but eventually upshift again if you don't slow enough to justify the lower speed. Of course in manual mode the paddles shift up or down and hold the gear until you change it.

samsausage

Not too familiar with the ZF8, but the ZF 9HP transmission in my 2015 Acura TLX was a nightmare and the reason I ended up selling the car. Slow, gear hunting, lurching etc. The car ended up needing a new transmission with only 2000 miles, even then it still shifted slow and would lurch when shifting from 2-3rd. They kept telling me "it just needs a software update". I know of one other person in my town with the same issues and also getting a new transmission, then selling the car.
After researching it I found that ZF had a major recall on a number of their transmissions, affecting lots of brands and vehicles using it, especially from Jeep and Acura.
I have a feeling the German cars using the ZF Tranny's have better integration, they can work more closely with ZF than the foreign manufacturers. Acura and the foreign (to Germans) brands using the ZF are using it more as a stop-gap measure to meet emissions regulations, until they can come up with their own solutions.

Acura ended up buying the car back from me and gave me extra $$ after filing a complaint, I then used that to buy the GS and have been much happier with its 6AT. My fave all time tranny is still the 7 speed I had in my Benz, 6-7 gears seems to be the sweet spot for me.

Just FYI, my paddle shifters in my 2014 GS350 AWD work even if I don't put it in M.