2010 has 5th Gear Grind on High Speed of 80mph above
 

I have a 2010 Mazda3 Touring with 250miles. I noticed that the 5th gear grinds on high gear.

Heres what happens; going 80mph, i take it out of 5th gear and put it in neutral, wait till the RPM goes back t 1k , I then step on the clutch all the way and shift into 5th gear -this is when i get the grind.

I have had this problem on old cars where the syncros failed, but i find it hard to believe that that is the case on this brand new car.

Anyone other Mazda3 owner experience this problem?

Can you test the same scenario i provided above and post back your finding

The cars under warranty, why not have the dealership check it out?

Wait, why are you taking it out of gear to even know this in the first place??? Just dont take it outta gear! JK that would bother me too and going to see if mine does that too on my way home tonight... Well not sure I wanna know though. That might drive me crazy...!

Post if you find anything out about that... Curious

Manufacturer finally confirmed the problem and will have the dealer replace the 5th gear and synchros replaced.

I would prefer they replace the car as this I only have 650 miles on it.

Anyone know how i can have the dealer / manufacturer replace this car after the repair?

Dealer finally finished the replacement of the 5th gear and synchros and guess what...... problem is still there.

dealer is awaiting instructions from, now, MAZDAJapan.

It has been 10days and counting. 10 more days and i can file for lemon.

Any transmission specialist out there that can explain why the replacement did not resolve the problem?

Why are you letting the rpm's drop so low before you shift, and why are you double clutching?

There could be just a problem with that large of a differential in gearspeed. Try revving it a bit before shifting it into gear - it would help the gears mesh since the speed difference isn't as large.
This should be a similar issue if you try shifting into second when you're going 80...

i got the car back and they ended up replacing the entire trans. i no longer get the grind from the same scenario.