Originally Posted by Josh@STILLEN

Oh good god.. I hope this isn't a trend.

I have a '04 G35 Coupe.. and have been through 3 replacement transmissions (4 total), and am waiting for this one to do the same thing, as it's always under 20k miles.. the quickest happening in less than 10k. (I was not alone with similar issues according to the popular boards.)

It starts by 5th or 6th grinding on quicker shifts, regardless of the clutch being fully depressed, and consistently got worse after time.

I will say I haven't had any issues getting things taken care of by Infiniti.. they happily replaced the transmission over and over again, with loaner cars and no tremendous hassle on my part, but I would hope that this synchro issue would have been resolved.

I was unable to get firm information on what the problem was, as the dealer would recognize the problem, and initiate the 'fix'.. aka a new transmission.

But this could absolutely be completely irrelevant, and unrelated.. I do not have detailed info on the differences in the two transmissions.