Hey guys, I just purchased a used 2016 IS350 with 56k miles, today was the first day I really put some time into driving it around and when I got back home I noticed a very subtle knocking sound when in reverse, also when I put in drive same sound, but when in neutral or park it sounds fine with no knocking. I read it could possibly be something with a flex plate or torque converter? Let me know if this is a common thing or an issue I need checked out soon. Thank you in advance!

 

It is probably normal, but a couple questions. Do you notice it happens only a lower RPM? Sometimes these engines have subtle noises that happen from day one thanks to direct injection and the general design of the engine. Do you have video or can you describe the sound a bit more?

 

Welcome to the forum!

Could you determine where the noise is coming from? Front? Back? Left? Right?
Is the car completely stock? Any aftermarket parts, i.e. exhaust?

 

Hey guys, I just bought a 2016 IS350 with 56k miles and I noticed a subtle knocking/rattling sound when I'm in drive or reverse (not while driving, just sitting still in gear) It's not loud but it's more noticeable in cold weather. But completely goes away when in neutral or park. The car drives fine and shifts fine, haven't had any slipping or acceleration issues.

 

Hey @Treymac95 , I've merged this with your existing thread on this topic. Any response to Sasnuke's questions?

 

Thank you for the responses! Yes I only notice it at low rpms (when I'm completely stopped in drive or reverse) and its sounds like it's coming from the back of motor area maybe the transmission/torque converter. I now know about the ticking sounds from the direct injection but this seems separate from that. I feel if I took a video you may not be able to hear it but I'll see if I can get it on video. at the moment I'm not sure how else to describe it, it's like a subtle knocking/chugging (ex: "chug-chug-chug-chug-chug") sound lol

 

Thank you for the responses! Yes I only notice it at low rpms (when I'm completely stopped in drive or reverse) and its sounds like it's coming from the back of motor area maybe the transmission/torque converter. I now know about the ticking sounds from the direct injection but this seems separate from that. I feel if I took a video you may not be able to hear it but I'll see if I can get it on video. at the moment I'm not sure how else to describe it, it's like a subtle knocking/chugging (ex: "chug-chug-chug-chug-chug") sound lol

 

So its sounds like it's coming from the back of the motor like the transmission/torque converter area. And no aftermarket parts! Completely stock. I was originally thinking it could be a sign of the torque converter going bad, but the car drives and shifts great.

 

If the sound happens when you engage D or R, and it's sort of a clunk, that's often mounts. Could be engine, transmission, or differential mounts. The latter two are most likely. You'll have to raise the car and have a good look around.

The torque converter is internal and is filled with fluid. so unlikely any noise you hear is coming from it. also if you had an issue with the TC, you'd really know it.

likely your diff mounts are loose. possibly trans mounts. raise em up. look around.

 

Did you find the problem? Im having same issue. Mine is causing a vibration around 900 rpm that you can hear inside. Sounds like a chug from the rear right of the engine near the intake manifold. Had the car on the lift and nothing is touching, almost sounds like a dull rattle on the frame. Won't do it when it's flat or in park. Only in reverse or drive.

 

Is this your first lexus?
And nope, haven't found the problem (if it's even a problem) From everyone that ive asked it seems to be a "car characteristic"? Ive had my lexus for well over a year and put 15k miles on it and the noise hasn't gotten worse and it drives great. I also just picked up a 2014 toyota tundra and it makes similar sounds. So it may be related to the dual port and direct injection and at a lower RPM you can hear it. I hope this helps, the noises annoyed me/bothered me when I first got the car but over time I learned it wasn't anything concerning.

 

It wouldn't be an issue but it's the vibrations/ growling sound it causes thats annoying. I believe it's starting at the front at the intake manifold but it echoes through the trans tunnel and can be felt in the cabin. Kinda ruins the drive if you know what I mean.

 

​​well, maybe it could be be your plastic engine cover? Or anything on the intake system isn't secured? My other questions are did you just purchase the car or have you had it for awhile and its making a new sound? How many miles on it and have the spark plugs been changed recently? I'm not a professional but I think bad spark can cause chugging/vibration/noise before it throws a code.

 

I've had the car for about a month now. It has 67k on it. I noticed it's been getting progressively worse. It's weird because it won't do it while it setting or driving flat but if its on a slight incline it gets significantly louder. I noticed today that if I'm going over a dip in the road the volume of it changes. Also gets more prominent with higher rpm. I would have sworn it was exhaust hitting the undercoated frame because it's a dull rattle. However we were able to pinpoint it to the engine bay. Sounds like a mini air compressor or exhaust leak. It's right under the manifold. The vibration is what's throwing me off though. Also not engine cover because it did it with it off also. I really don't want tontake it to the dealer just to have them say they couldn't find it.

 

Hi

Any update about the issue?

Thanks