'17 Accord LX 2.4L 6MT 101k on it. Owners manual and all online say 2 qts needed.
Out - good question. Probably GM Synchromesh FM. My book has changed with Ravenol MTF 2 at just over 50k when I bought used. 2k later I swapped a quart of Redline either MT-85, that I know I had from prior, or I bought some MTL 75W-80. I didn't like the cold weather shifting of the just Ravenol at least at that time.
I thought I had swapped about 25k after that to GM Synchromesh FM, and I only have 2 bottles left of the 4 I ordered so must have missed writing it down. How dark is the Synchroshift FM as compared to others? The fluid that came out was definitely darker than what ai put back in.
Any way - IN - 1 qt of Ravenol MTF 2 and 1 qt of Pentosin MTF 2. Short drive around for errands feels like it's shifting a bit smoother, maybe just in my head. Both of these are on Molakule's list of MTF to be in same CST range as the factory Honda MTF.
I still have in my stock/stash 1/2 qt BG Synchroshift II, 4 qts of Pentosin MTF 2, and 2 qts of GM Synchromesh FM. It will be a while before I buy more. My Accord is the only manual transmission on the fleet. If I don't like how it feels or shifts in the different temperatures, I'll try maybe just Pentosin, maybe back to Synchromesh, maybe buy Honda MTF.