Hey everyone, I'm a new owner of a 04 S2000 with 133k miles!

I'm currently diagnosing some 2nd gear issues that i have when shifting from 1st to 2nd. Initially when i test drove the car in warm weather i did not experience any issues shifting. It was about in the 80's here in Texas. I drove it home and the temperatures dipped to the high 40's when i drove it home and of course that is when i got the 2nd gear grind occasionally on the drive back. I was doing a bunch of reading and cross referencing and i have done these so far:

Got rid of clutch free play
Noticed that the clutch fluid was below minimum and really dirty. I changed it via the syringe method and refilled / cleaned the container.
Started shifting near 4k rpm

I noticed with these changes it got rid of 90% of the grinding. I'm changing all the fluids this week including the transmission since the last date is 2024 for the transmission. Should i try changing the clutch fluid again after driving around a bit? I did notice that because of the gear grinding i sometimes psych myself out and not press the clutch all the way but if i deliberately think about the process i don't get that 1st to 2nd grind but it still feels a bit weird compared to other gears.

I read through the owners maintenance logs and he had the clutch replaced at 100k miles and also took it into service for gear grinding at 120k miles. The dealership recommended changing some clutch components but I'm not sure since the clutch was just recently changed i don't think it would be the issue. He denied the repairs. I'm guessing the free play and clutch fluid was causing his issues. Am i on the right path here to getting the issue resolved?

 

try Amsoil manual tranny fluid (5w30 ) , it works well when cold.

 

10 12 years ago when I first bought my S2000 I posed the same question and was advised to not up-shift until 4300rpm. Despite being certain this was sending the New Guy for a left-handed monkey wrench I tried it. Darned if it didn't work!

-- Chuck

 

yeah , slow lazy shifts at lower rpms never seem to work as good as that ^

 

There is the unfortunate worst case that the synchros are worn.

You can try the different oil as mentioned. I tried a few when mine first started, none really made any difference. And just in case you hear it from other Honda people, I tried the GM Synchromesh lots of them love and it was far worse in both shift feel and if anything the grinds were worse with it. Mine had worn synchros and I ended up finding a used transmission with lower miles and swapped it in. Finding parts to rebuild our transmissions is getting pretty hard so I still have the old one sitting here. Maybe the new parts program will help!

Now, it sounds like someone replaced the clutch, then 20,000 miles later reported grinding issues. If the people that replaced the clutch did not grease everything properly (like the spline shaft and the throwout/release bearing) it could be dragging a bit which could cause some grinding on faster shifts. But figuring that out means pulling the tranny so make sure hydraulics are all good and maybe try some different oil options in the transmission. I like Redline personally. It can feel a tad bit notchy when cold but that goes away quickly as it warms up.

 

Try running a different gear oil, like others said. I am currently running Royal Purple Gear Oil. I've run Redline in the past without complaints, but the Royal Purple seems to hold up better on a hot day. AmSoil is also recommended. If it still has an issue, follow engifeer's advice.

 

I went ahead and had all the fluids changed today. I picked up Royal purple since it was on sale for the transmission. Got no grinding on the way back after changing the fluids. Just got a notchy feeling for 2nd gear but after it was warmed up it felt good. I also got no grinding before i changed the all the fluids. On the side note, i found the previous owner had the oil pan drain plug threads stripped so time for a new oil pan now lol. Thanks for all the advice everyone!

 

If you are talking about the engine oil pan drain bolt, you may want to try this.

 

I've thought about that plug, i think i will just bite the bullet and get a baffled oil pan since i was going to primary make this into a track / weekend car anyways. I think it will be better for the long term.

 

Be sure to get the proper sealant, like HondaBond HT.