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EbonyGraph · 2025-09-29T08:39:59-0400

Hi - Last few startups, I am noticing my 2016 making weird noises at startup. As soon as I start the car, the RPM drops to around 1100 and fluctuates between 1000-1100 RPM making some weird noise, sounds more like a low volume high frequency metallic noise only when RPM needle fluctuates. After about 30seconds after startups, the RPM drops below 1000, and everything is back to normal. Till now, have not noticed any difference is driving. Per maintenance history, transmission fluid was replaced at 52K miles, now it is at 88K miles.

Is my ZF9 tranny dying? Please share if other ZF9 MDX owners also noticed similar issue before the tranny eventually failed.

datechboss101 · 2025-09-29T09:07:29-0400

Those are RPMS are normal on cold startups. Happened on my MDX and my parents POS Rogue. Now for the noise, can you please upload a video here so we know what you are talking about?

EbonyGraph · 2025-09-29T10:25:20-0400

hmm... my MDX never did that in the past even during winters or when sat for weeks without being used.

mvl · 2025-09-29T09:27:17-0400

Timing belt tensioner? Mine went at 75k w similar symptoms.

EbonyGraph · 2025-09-29T10:14:59-0400

Did not notice any noise or RPM fluctuation when I started the car the second time today, will try to capture the noise and post it when I am able to.
I have checked the TB tensioner noise on YouTube, my car does not sound like that.

mdxstang · 2025-09-29T14:36:39-0400

I don't think anyone can help you based on the description. I suggest doing what you can to isolate the noise by replicating it by starting it while you have the hood open and your ears in there. See if it's the left, right, front, back area of the engine bay or maybe it's not even the engine bay.

Lots of things can be a source of noise so I wouldn't immediately just to an extreme case of a tranny issue. Maybe it's an AC Compressor clutch, something related to the TB, a water pump bearing, a loose underbody shield rattling, or any of a bunch of other things.

EbonyGraph · 2025-09-29T15:17:09-0400

Agreed. The noise can be from anywhere but got worried since the noise was in Sync with RPM fluctuation. I pay very close attention to how my cars behave, this one definitely caught my attention.

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