Just FYI on this. Symptom was a thumping sound when the drivetrain was engaged -- not with clutch pedal in, and not in neutral. Thumping was timed with wheel rotation.

85K miles. Ring gear on final drive popped 3 teeth. My mechanic said the rest of the transmission is pristine, with no signs of fatigue, abuse, or grinding. Clutch in awesome shape.

No idea how this happened. He said that when he's seen it, it's from spinning both tires off of ice onto dry pavement, or a sharp turn with both wheels spinning. Neither of those happened, so I'm chalking it up to one minor QA issue somewhere in the alloy or similar.

Glad to have it back. $2650 out the door with tax, but this shop is awesome, and worth some $$ (Eagle Transmission in Austin, TX).

 

Wow, that sucks. Huge money to have to put into a 9 y/o car, but oh well; not much choice I guess. Hope you weren't planning on getting rid of it anytime soon, it will take awhile to amortize that repair.

 

Yeah, it sucks, and as you said, really no choice. We'll have it another year or so. I guess no sense worrying about it, sometimes things don't go as planned.

 

If it is the final drive gear, it is a known failure that Acura is not willing to acknowledge but they have an internal document stating this issue. Please read more about this in this post....

https://acurazine.com/forums/1g-tsx-problems-fixes-128/04-tsx-6mt-front-end-sound-clicking-through-gearshift-667479/
you can read my post starting post #26 about my experience....