This has been my experience exactly with the 500. Slightly clunky shifts when the transmission is cold, primarily when it shifts from 5 to 3, and then 3 to 2. But when it's warm, it's like butter. I attribute this quality to the assumption this transmission is designed to handle 472hp for 2 million miles and prioritizes strength and reliability over perfect smoothness. Having driven a 2017 C63S for 2 years, this is an improvement in daily drivability. That transmission was better with the paddles, but clunkier/ rougher around town than the IS500.

 

I don't know if mine's ever been smooth like butter in manual shift mode. Even after driving in the mountains, which was an hour drive to get there, it still can be a little clunky on downshifts or even upshifts with anything less than 75% throttle. When I drove Tony's car, it was pretty smooth, though, even in manual mode. I could feel the downshifts at low speed/RPM, but not at higher RPM. This was a pretty short test-drive though, so who knows?

edit: Maybe for the 350/300 RWD models, we could continue using the following thread: https://www.clublexus.com/forums/is-...t=speed+smooth

 

Some good discussion about how to properly downshift here:

https://www.clublexus.com/forums/rc-...-about-it.html

 

OK so I've owned my 500 for a week now, and I have noticed the 4-3 downshift is pretty noticeable. It becomes completely smooth and normal after 5 minutes of driving, but the first couple of slow-downs will probably elicit a little lurch. The car has under 400 miles on it. So I'd say this is normal behavior, sadly.

 

To the OP;
I just came home from taking my car out for a spirited run and got on it the most since purchasing it 2 months ago. I just turned 2000 miles even. I know exactly what you are talking about. I find it awesome from 3 to 2 to 1. I recall it is exactly how I remember the one time I was able to take a single lap in a real race car. It performed just like my memory.. Rough going down from gear to gear from 3 to 1. I find it exhilarating. The torque load being put on the tranny going down is alot. It speaks volumes for an auto tranny to pull this off. Why my generation was reluctant to embrace auto trannies in sport performance cars, but Lexus nailed it!!!! I feel the power of the engine downshifting and the responsibility I have holding the wheel and responding in kind. Whether it be to continue to downshift or get back on it, which is what the tranny is prepared for and built for. To be durable! So no, I do not think this tranny is anything less than awesome. Two more gears would be better. It is a driving machine. I think Lexus nailed it! As stated many times, this car combines comfort, luxury, performance and peace of mind of durability. No other car comes close. None. And yes, I have full reason to have confidence in my driving training.

 

The rough downshifts in automatic mode ease up with more miles. I'm at 7,900 miles and it's much less noticeable

 

That's good. Last night I went on an extended drive - trying to get these break-in miles over with! - and it was perfectly smooth after 20 or so minutes. No lurches at all.

I think it's important to frame this transmission for what it is, in context of its development.

It was specifically made for the IS F. At the time it was released, the IS F had a transmission with the fastest up-shift in a production car at as low as 100 ms (sometimes quoted by journalists as "about 0.1 seconds"). Even today, the way it shifts is pretty competitive with something like a ZF 8HP... while the ZF is, of course, smoother overall, the actual speed of the shifts is pretty much the same if not somewhat slower in some situations. With the IS F being a performance-oriented car, the downshifts are also intended to provide engine braking. As a result, sometimes they come off as being a bit abrupt or firm. I actually like this. It makes me feel like I'm really doing something when I use the transmission! I could go on. But anyway, I like that we get all this high-performance capability while retaining some degree of daily-driver livability with this transmission. It has its hiccups, but nothing more than you'd get in many other brands' drivetrains. Heck, even my wife's 330i with its unassailable ZF transmission still sometimes lurches if I am going through a roundabout and getting back on the gas when exiting, or when taking off in slow-and-go traffic - things the Lexus transmission doesn't struggle with at all.