I have always had some issues shifting sometimes in my 2004 MT. Reverse is the trickest one. Sometimes I have to try a few times before it gets into gear, otherwise it grinds a bit when I let the clutch out. I am pushing it down since it clearly isn't trying to go into 6. Sometimes it doesn't grind until I hit the gas (like I get it into gear, let out the clutch to try to reverse, grind).

The other issue I have sometimes is when I am driving, after a long drive session, it's hard to shift into first. Like the gearbox is resisting moving my shifter.

I have a brand new master, slave, clutch pedal and fluid (brake). I probably sould replace my transmission fluid but this has always been an issue. It doesn't always persist and is easy to eventually get it to work correctly.

Thoughts besides fluid? My transmission / gearbox shitting out on me?

 

Definitely a case for fluid change and verifying that the clutch pedal is correctly adjusted (you can google what that implies). Reverse is like that, sometimes you need to inch the car forward to change the cog alignment to get into reverse.

First should not be difficult though, but if you say it's heat related, I'm sure a good fluid will help. To be clear, is that shifting into 1st from a standstill or down from 2nd while moving? You shouldn't really be going down into first, and it can be difficult in that scenario.

 

https://www.rx8club.com/series-i-tec...7/#post4816868

for reverse when it won't go in: put it back in neutral, let clutch pedal out for a few seconds, then push clutch pedal in and try again.

You might need a new shifter if the plastic bushing that engages the shifting mechanism in the trans is worn/sloppy, same for the main pivot bushing within the shifter. You might also need to check/replace your motor mounts and rear diff mounts because these get sloppy over time time too and can affect shifting while driving.

 

The shifter itself is new (I have the SS installed). I'll double check the clutch pedal, though I had Mazda adjust it for free when I brought the car in for the recalls.

I'll go ahead and do fluid changes since it's probably around that time anyways.

In regards to shifting into first. It's not always, and this is from standstill. Shifting while driving seems normal.

 

Switch to a good fluid. I prefer Red Line MT-90. It's surprising how much difference it makes.

Folks are making lots of noise about Ford's XT-M5-QS fluid, if you want to try that. I haven't tried it yet but will soon.

You don't say how may miles you have, but depending on how hard you drive it, how many miles it has, and how good you are at shifting, it may be shitting out on you. The Series I transmissions are good enough, but not great.

 

You can try the same thing I mentioned about reverse previously and use it for first gear too when it seems not to go in gear.

 

My S1 has ~115k now. So that's why I was a bit worried on if the transmission is going but I am going to try fluids since that is a far easier test than to try to get a new transmission.

 

You'll be shocked how much of a difference it makes.

Fact is your transmission is probably fine. I've been abusing mine on-track for nearly a decade, 3-4 almost always grinds when hot, and it still hasn't exploded. Even have an S2 trans I bought years ago sitting in the garage when I thought an S1 explosion was imminent. Still waiting...

And trouble getting into reverse and first are both common, and a looong way from needing a new transmission.

 

Well that's good and bad I guess haha. I'll just swap in some new fluids and hope that takes care of it.

 

So, I finally changed out transmission and diff fluid and the car does **** better. But, still, after a long time of driving the car, the car is super hard to shift into sometimes.

I found a workaround where if I can't shift into reverse or first, I can push it (clutch still in) into second, and then it can shift into first. I do not have a stainless steel clutch line, but it is a new Master, Slave, Clutch Pedal and fluid. Could the clutch line be bad or is this looking like a bad transmission/syncro?

 

What fluid did you go with?

Your description of having to go into a different gear before your desired gear while stationary sounds like every manual gearbox I've ever had. Sometimes the teeth just don't mesh properly and shifting into another gear moves things around a bit.

TeamRX8's recommendation of putting it into neutral for a few moments is the same principle but it just uses (fluid?) drag between the various shafts/gears to accomplish it.

Does this happen every time you try to shift into first or is it just once in a while?

 

I'm sorry, but I just can't help but notice the typo.

Lots of people recommend the XT-M5-QS fluid here.

Reverse gears are not synchronized so it's pretty normal. When I had my 5-speed Corolla, I had trouble going into reverse half the time. Double clutching solves the problem every time. I never bothered with the fluid in that car as it's just a beater.

As for first gears, some cheap, old cars don't have synchronizers for them, but I believe RX-8 has all the forward gears synchronized. You should be able to shift to 1st at any speed below 20 mph.

Personally, I never had issues going into 1st and reverse on my S2 gearbox.

 

Trans: RedLine MT-90 GL-4
Diff: Ensos GL-5

Both with weight of 75w90.

In regards to this happening all the time, no. This only seems to be very difficult after driving the car for ~1 hour+ and it gets hard to move. Also, my trans seems to be leaking heat up to my shift ****, etc. So, I have to stop that heat from leaking into the cabin.

Sometimes, one issue I see a lot is getting it into reverse. Sometimes I don't get "into" gear and it just grinds when I go to release the clutch. I can then just put it back into neutral and try again and it works. That seems to happen a few times, regardless of how many times I've driven the car.

 

The reverse thing is normal-ish. The heat could be coming from your cat more than the trans. I'd get that checked out.

 

Redline MT-90 Fixed the shifting in our car. It when from grinding/notchy shifting to the best manual shifting transmission I have ever driven. It took about a month for the complete improvement.