davidg7706

Hey everyone,
I recently went for a nighttime drive on a local back road in my base '22 IS350 with a friend leading in his CT200h. I was careful not to drive too fast since I wasn't very familiar with the road, and it was dark. I maintained a speed slightly above the limit, only slightly passing 60 mph a few times on the empty road.

During the drive, I switched to manual mode to better control my speed, mainly staying between 2nd and 3rd due to the long AF gears on this car's 8-speed. When we reached the dead end at the top of the road, I noticed a burnt rubber smell near the left rear tire of my car, but not from the right.

On our way back, with the car in auto+sport mode, it unexpectedly downshifted on a steep turn, causing a redline that wouldn't change. I had to intervene to correct the gear manually. The dashboard display was confusing, indicating 7th gear when it felt more like 5th or 4th, but eventually, after a minute of this, I corrected it by putting the car in manual and then putting it back into auto.

After stopping at a market, the burnt smell was still noticeable. My friend thought it was the clutch, but it seemed more like tire burn to me due to the open diff (still pissed the Torsen LSD didn't come standard with the whole F-sport lineup, lmao). When I got home, the smell had disappeared, leaving me uncertain whether it was due to clutch strain or the differential causing more wear on the left tire.

Am I overreacting by being concerned? Open-diff or something else?

Edit: I'm a long-time lurker but never got the courage to post till now, so that's why my account is new lol

arentz07

How long was this road? It sounds like you weren't doing anything too crazy, but you were chasing a CT... not exactly like chasing a supercar.

Did you have traction control off? If not, you would have seen the TC light on the dash if you were actually spinning up the rear tires. However, sometimes on my IS 500 I also get a burnt-rubber type of smell from the rear. My best theory is that it is due to ESC intervention since the brakes usually also seem hot when I smell that smell. I never experienced that on my IS 350 as far as I can remember, though I did smell what I assumed was brakes on longer spirited drives in the mountains.

I frequently had a rotten-egg or sulfur-like smell from my IS 350 when I drove it hard. I don't have that smell on my IS 500.

davidg7706

The road is, at best, 3-4 miles long, so the length shouldn't be the issue as far as I know?

As far as traction control was concerned, I didn't turn it off, and the light never came on, so I wasn't going past the grip limit. I think you might be correct with the assumption of the ESC intervention, but it never felt like the car was struggling enough even to need it, which was odd for sure.

But what concerned me was also my transmission going downhill. Usually, I figured the Lexus auto would be able to handle itself, but the random red line that didn't correct for a while until I made it was concerning. It was almost as if it wanted to up-shift but couldn't figure out when. Is this normal?
(Side note: Tbh, the CT might not be fast on paper, but holy crap, I was surprised at how that thing rips through the canyons. My buddy left a solid 30-second gap on me while I was pushing the car on a different road; crazy underrated car IMO lmao .)

frid4

It all depends on the driver, for how fast you are in the canyons.

As for your downhill if you're in sport + mode with auto the car will tend to rev hang as it thinks you will put more gas into it.

arentz07

I guess by "rev hang" you mean, it won't upshift at redline right away? I have seen that in both my IS 350 and my IS 500. It happens when going downhill. This is partly why I recommend manual mode for spirited driving.

frid4

Yea very noticable in Sport + its the way Lexus tuned it to make it feel more sporty I guess.

cerbois

REV hang is when you take your foot off the gas (on a manual trans) the RPM takes a second or so to start to drop making it annoying for smooth fast shifts. It s done for EPA reasons to burn cleaner. It s hated by auto enthusiasts and can be tuned out of the ECU by some tuners.

I don t know but maybe it s tuned into some auto s too, (for the same EPA reasons)

arentz07

Yeah I am pretty sure that's not what is being discussed here. Good to clarify. If someone says "rev hang", that manual transmission behavior is most likely what they're referring to.

In this case, I may be a little lost.

Either way, I've seen it fail to upshift at redline before on every IS I've owned (2016 IS 300 AWD, 2021 IS 350 RWD, 2023 IS 500).