I've noticed in traffic the shifting on my rear drive IS350 is a bit odd. It's not slipping, but its like it forces it into the next gear from 1-2 somewhat abruptly, and its a lot less smooth than 3-4 shifts.

It's only at low speeds, in traffic. The throttle can seem a bit, maybe jumpy, on occasion in the same conditions. In normal stop and go (not traffic) conditions and harder accelerations it is totally fine. So far I've chalked it up to having a quirky 8 speed transmission that likes to shift early. My car has roughly 19,000 miles. Any others experience this?

 

The 8 speed tends to learn some weird behaviors over time. Highly recommend disconnecting the battery for a few minutes as a first step.

 

I was afraid of that, since I know I'll lose all my radio settings.

 

You don’t have to disconnect the battery. I don’t know why ppl do that...
In the engine bay fuse box, simply pull the ECTS fuse and EFI fuse for 5 minutes then put them back in.

Just don’t panic when the car doesn’t start the first time after doing this, completely normal, just wait a few seconds and start it again.

easiest and fastest way to reset the ECU and you lose no settings.

 

There are multiple fuses labeled EFI, which one is it?

 

EFI 1. (Main) 25amp
are u sure u don’t see a ECTS fuse? Look on the cover for the fuse box it should be labelled and ECTS should be there.

 

Sorry it’s ETCS, not ECTS


look where the 3 slots labelled “spare” are at the bottom to the right, the 10amp ETCS fuse is located a few spots above them...see it?

 

Try playing around with your throttle application in traffic. using a touch more throttle (past this certain threshold) tends to smooth out the shifting. My other car, a Mazda, shifts a little roughly into second gear at around 1500RPM unless you bump up the RPM's to 2100+ a tiny bit.

If the jerky shifting is really bad could point towards a faulty transmission shift solenoid(s)

 

Even my 6-speed shifts a bit "weird" from 1 to 2 compared to the other shifts. It's not as smooth and came across as abrupt when the car was brand-new. I have just learned to drive around it lol.

 

A good idea. However, as my earlier post indicates, you also have to recognize the car has its quirks. It's important to note whether the car has always shifted the way it does, or whether the behavior is new.

 

Sure. I agree with everything you are saying. However, at a mere 19,000 miles, I don't think OP's car is likely to need a fluid change yet. Yes, it is possible, but unlikely unless OP has some relevant information to indicate some "unusual" usage patterns, like driving up and down steep grades all the time for instance.

And with respect to the "dumb" statement, let's not pretend that the transmissions in the IS are the best-programmed ones out there. I found the AWD model's transmission to be a bit clunky at first, but over time I found myself liking it more. In retrospect, I have driven other cars since owning my IS with far easier transmissions to drive, and just took some time to learn my IS's. Just to give an example, so it doesn't sound like I am just making things up, I have rented a Jaguar XF 35t on Turo, and the ZF 8-speed in that car was simply unimpeachable in any regard. Nothing it does elicits a complaint. The Porsche PDK in the Macan was also phenomenal. I couldn't think of anything I would change about it - it was both smooth and fast. The 10-speed in the new Camaro SS, too, is an excellent transmission - it essentially drives like a 10-speed version of the ZF. It has very little paddle delay and crisp, yet smooth shifts. In comparison, the IS's transmissions do feel a bit dated. That's not to say they are bad - in fact, the 6-speed in particular is impressive considering it's over 10 years old yet still delivers quick shifts, and the 8-speed provides a nice dual personality between casual driving and sporting driving that the 6-speed can't. That said, neither of them is as smooth or quick as any of the examples I've listed above. So in other words, I think we all know the transmissions are good, but it's all relative - and relatively speaking, the IS's transmission offering are pretty weak, both in terms of performance and programming.

From day one, I've noticed the 1-to-2 shift in my IS 300 AWD "takes some getting used to". That is, it has always been a little sudden and has actually only improved as time has gone on, not gotten worse due to fluid. Whether the OP has a different issue has yet to be confirmed.

 

This "quirk" is actually somewhat common. Not all consider odd behavior. I've resolved this is normal for alot, if not all the 8 speeds. I've done some reading on the behaviors of the trans over the last couple years.

One thing to be sure of is your not in manual mode, or sport mode. Those are sure ways to have some weird shifting in traffic.
in normal auto mode I'm super smooth 95% of the time if not more, but then im in traffic +40 mins a day so my trans may be more learned than others.

 

The 8 speed in my car shifts smooth 99% of the time in stop and go traffic, only occasionally will I feel the shift between 1st and 2nd. Usually that's either while in sport mode due to I'm assuming torque convertor lock up, or if in normal mode under throttle while accelerating from a slow creep. It's pretty rare.

 

It's not a major difference, and again its only when creeping along in traffic or similar conditions from a standstill. Only from 1st to second gear. It may be my perception of it. But it seems many in this post are reporting the trans having its quirks. It's not every time, nor is it shaking the whole car or something truly dramatic.

 

FYI, I just got it back from service, and they can reset just the transmission computer using tech stream. I'll report back if it relearns traffic shifts