Join Date: May 2009
Thanked 60 Times in 39 Posts
JFI, this subject -- i.e., whether a particular manual transmission fluid (MTF) will improve shifting or mitigate grinding on the 1st-to-2nd gear shift -- has been discussed and debated extensively on other Honda boards over the course of several years. (See, for example: .) And there's no question that GM's "friction modified" MTF (now sold by AC Delco, a GM subsidiary) will improve shifting performance. ( The only question -- still unanswered btw -- is whether there are any long-term, unreported negative consequences. That debate is still ongoing. What clouds that issue is whether those who use alternative MTF's are also owners who beat the hell out of the cars.
A more conservative choice (IMHO) is Amsoil's Synthetic Manual Synchromesh Transmission Fluid. It's a bit more expensive, but Amsoil was one of the first, if not the first, to offer a fully synthetic MTF. FWIW, I used it for a least eight years in an '02 Civic Si, a car which was notorious for shifting issues, and I thought it was excellent product. If nothing else, it greatly improved cold-weather shifting, and unlike the complaints of some that GM's MTF is only good for, say, 10k miles or so, I didn't any decline whatsoever in Amsoil's performance over time. I changed MTF once at 2k miles and left the stuff in my Civic for years. I should also mention that I never beat on my cars, which may explain why I've never experienced a problem using Amsoil's MTF.
As others have noted, nothing you pour from a bottle will fix a mechanical problem. But it's also true that there are other fully synthetic MTF's, such as Amsoil's MTF, that will improve shifting performance.