I looked around and couldn't find anything posted about this. I just bought my 2004 RX-8 used from a friend. It's only got about 39k miles on it and everything is good except that when I'm in first gear and I get it over about 7k RPM and I try shifting to second it grinds. Every time. I'm not very mechanically inclined, so i was hoping someone might have an idea about what the issue is. Any help will be greatly appreciated.

 

I have an '04 that started grinding going into 2nd around 40k. I swapped the transmission oil out at 45k a couple of weeks ago - 75% Amsoil GL4 w/ 25% Amsoil Synchromesh. It shifts smoother in general, but 2nd now seems to grind more often - I think it's the sudden change in the weather in AZ to cooler temps. I don't think I have to be at higher rpms to get the grind, it's usually when the car isn't warmed up. I'm blipping to 4k before driving now to splash lube the transmission. So far it seems to be working since 2nd hasn't grinded on me in the past weeks since starting this practice.