[Crozetian]

I have posted here (and elsewhere) on my new, 08 STI's occasional gear grinding when upshifting from 3rd to 4th. Occasional, by the way, is once or twice a day of 50-100 miles, many of which are on back roads with much up- and down-shifting.

The dealer replaced the gear oil with the Subaru Extra S about 1000 miles ago, and that either made no difference or possibly made a very slight improvement. The problem is that they can't duplicate the problem because it only happens once a day or so and I can't force it to occur (high/low rpms, fast/slow shifting, etc.)

I'm going to leave it at the dealer next week for a few days (they're giving me a rental), but I'd appreciate any thoughts any of you have. The grind, as I said, occurs only when upshifting form 3rd to 4th, and it always occurs while leaving 3rd as opposed to going into 4th, if that makes any sense. That is, I hear or feel it immediately upon moving the shift lever out of 3rd, not when it's snicking into 4th. Its nature varies from a loud grind, of the sort that would be made if the clutch weren't depressed, to a mild something's-not-right vibration I can feel in the gear knob that even my passenger can't here.

Does this sound like a bad synchro? Something wrong with the clutch? Something else?

Thanks....