I've run into a problem which has me suspecting bad synchros.

A few months ago I changed out the transmission fluid in my AP1, in my lack of foresight, I put in some regular shell gear oil. Soon after, I noticed I could no longer downshift into 2nd gear and had to come to an almost complete stop in order to get into 1st, even if I rev-match. I discovered I could only get into 2nd gear if I double-clutched and quickly rev-matched, and even then the shift was a notchy.

Other than that the transmission rows through all the gears just fine.

Does this look like a synchro issue, or simply change the fluid back to Honda MTF and be done with it?

And if it is synchros, which pn's do I need for the rebuild?

I found the gear set from honda's website

PN: 23432-PCY-306

What else would I need?

 

Change your fluid to honda MTF immediately. do it after a long drive when the trans fluid is very hot.

Fluid change should fix it.

 

check the label of the gear oil you used, if it is a GL-5 fluid and it contains sulphur I'd seriously consider flushing the tranny by doing a fill and drain prior to the final fill of Honda MTF. You want to get out as much sulphur as possible as that's what hurts brass syncros.