Transmission Grinds/Lockouts Causes & Solutions

[FK8_Track_Pig]

Red star motoring uses and recommends Motul ATF for the Type R’s. I can’t find enough feedback though to feel comfortable trying it. I have the AC Delco FM but occasionally will get the 1-2 grind.

Thats interesting. Those guys do run their cars hard though, at least it’s not some dd grocery getter guy putting out info like that. Would be interested in having them explain why they use atf.

I had the typical 2nd gear grind, changed to gm synchromesh and it lessened, adjusted the clutch pedal and it didn’t seem to do anything. Bought a modified cmc from a member on here that makes them and the grind is completely gone. Still feel like the 1-2 shift can be a bit smoother but the grind is gone so I’m happy. Might modify the slave cylinder to see if that does anything. I would only get 4th gear lockout occasionally but hasn’t happened yet with the modified cmc.

Sponsored

 

[jmark]

That’s the one I use.

Great thread. Does it seem to make a difference over the OEM fluid? How much is required? 2.3qt?

 

[Lust]

Great thread. Does it seem to make a difference over the OEM fluid? How much is required? 2.3qt?

Made a big difference for me. Shifting overall was just a bit smoother especially on track where it would get hot. Yes 2.3qt

 

[jmark]

Made a big difference for me. Shifting overall was just a bit smoother especially on track where it would get hot. Yes 2.3qt

Thanks. I am using the Motul motor oil you are running. May give the Motul tranny fluid a shot next oil change.

 

[Lust]

Bump

 

[flacobill]

I’m not experiencing a grind but would like my clutch to engage slightly sooner like my previous FK8
Guessing it will be slight cmc rod adjustment & possible pedal travel as well?
Is the factory adjust in service manual on point?
Thanks

 

[Lust]

I’m not experiencing a grind but would like my clutch to engage slightly sooner like my previous FK8
Guessing it will be slight cmc rod adjustment & possible pedal travel as well?
Is the factory adjust in service manual on point?
Thanks

Sooner as in when you push on the pedal? If so, you will want to adjust the pedal free play.

 

[NH_R32416]

Thank You so much for this write up, Incredibly useful.

 

[martindtjr]

Thank You so much for this write up, Incredibly useful.

Thanks for the info. I adjusted out the slack, like you mentioned. I finally drove my car and no 1-2 grind.

 

[Lust]

Bump since this got buried

 

[Agent Eagle]

Wow..., this is the most intelligent, logical, informative response to these issues, that I have seen, for the last 5 years... Glad there is somebody out there that knows what they are talking about !

Thank you

 

[Tyrannosaurus WRX]

It's writeups like this that make a platforms forum next level compared to other cars out there. Thank for for your time on this!

I have 14,000 miles and consider myself a great driver as every car I've ever owned for the last 23 years was a manual. With that being said I've had the 1 to 2nd gear grind twice in 14,000 miles. But that's twice to many for me. The most recent time was a bad one and I still can't help to feel did that happen because I got just a tiny bit lazy when I shifted??

I am very curious about a modified CMC as mentioned above I don't have this grind as a chronic problem, but would like to NOT have it happen ever again. Also I wonder if a modified CMC would change/improve every day normal driving feel?

 

[Dave B]

Thanks again for the write up and the bump Lust. 2 questions.

1) I switched recently to the AC Delco fluid and at first everything did seem that little bit smoother. OTOH, I track my car quite a bit and am concerned about the AC Delco fluid when it gets heated as in during track use. It is listed as being "semi-synthetic" which to me indicates it may not be able to handle high heat. Has this proven to be a problem?

2) Is there supposed to be any free play with the clutch pedal? I would have thought with a hydraulic clutch there should be none but the only way to find out would be to lengthen the clutch adjusting rod until there is some free play then tighten again. To be fair, I have not had any issue except the very occasional 5th to 4 th downshift which may well be a technique issue. I never shift quickly from 1st to 2nd so never experienced grind.

When I look at some drivers' in car videos, they all seem to shift faster and harder than I do. Think I will need different cables and shifter to do that with confidence.

 

[Lust]

It's writeups like this that make a platforms forum next level compared to other cars out there. Thank for for your time on this!

I have 14,000 miles and consider myself a great driver as every car I've ever owned for the last 23 years was a manual. With that being said I've had the 1 to 2nd gear grind twice in 14,000 miles. But that's twice to many for me. The most recent time was a bad one and I still can't help to feel did that happen because I got just a tiny bit lazy when I shifted??

I am very curious about a modified CMC as mentioned above I don't have this grind as a chronic problem, but would like to NOT have it happen ever again. Also I wonder if a modified CMC would change/improve every day normal driving feel?

A modified and adjusted CMC will provide a significant difference in shifting feel

Thanks again for the write up and the bump Lust. 2 questions.

1) I switched recently to the AC Delco fluid and at first everything did seem that little bit smoother. OTOH, I track my car quite a bit and am concerned about the AC Delco fluid when it gets heated as in during track use. It is listed as being "semi-synthetic" which to me indicates it may not be able to handle high heat. Has this proven to be a problem?

2) Is there supposed to be any free play with the clutch pedal? I would have thought with a hydraulic clutch there should be none but the only way to find out would be to lengthen the clutch adjusting rod until there is some free play then tighten again. To be fair, I have not had any issue except the very occasional 5th to 4 th downshift which may well be a technique issue. I never shift quickly from 1st to 2nd so never experienced grind.

When I look at some drivers' in car videos, they all seem to shift faster and harder than I do. Think I will need different cables and shifter to do that with confidence.

AC Delco SMFM will be fine for track use though you will need to drain it more frequently. From factory, there's a good amount of free play in the pedal assembly itself. This it to ensure people aren't riding the pedal and glazing the clutch. I'm sure most of us rest our feet on the dead pedal but this is just a precaution for them I assume. I don't think you'll need to do much else than the pedal adjustment and fluid TBH. Though the shifter does improve feel significantly.

 

[RickyJeezus]

I wanted to chime in as I've upgraded the fluid, and just recently finished installing the Acuity Stage 3 shifter with bushings.

First off, my FK8 is a 2021, fairly late production I think im somewhere around #53,000? I have to double check. Instantly driving off the lot when I bought the car I was getting shifter crunch...which I assume is not the 1st to 2nd grind that everyone is talking about. I would get this crunch in alsmot all throws, I'm talking 1st to 2nd, 2nd to 3rd, 4th to 5th, 5th to 6th...and most downshifts too.

I noticed, though, after my car was parked out in the sun for a little while, that my shifter definitely felt better and shifted smoother, so I figured fluid should be my first step. I switched to Amsoil at around 6-7k miles and definitely noticed smoother shifting. It felt like what it would feel like after being parked out in the sun for a while. The problem wasn't completely fixed though, I would still get an inconsistent crunch in the shifter, and after driving a few other FK8s that were stock, I still noticed that everyone elses shifter just felt tighter, you can tell as soon as doing the neutral check that my shifter felt sloppier. Also, I never got the first gear lockout until I switched fluid, which I thought was weird.

I finally got my hands on an Acuity stage 3 kit, and took me and a buddy about 5-6 hours to install it including the bushings, and what a difference it made. It feels like what I expected it to feel like from the factory. The biggest difference I noticed was that the shifter play while in gear was minimal to 0. Only in 1st and 2nd gear I still have slight play, but I jus a much more confident feel in the shifter.

Now with all that being said it still is not perfect, I still get an occasional 1st gear lock out, and a friend was driving the car and got the 1st to 2nd grind (but they were doing a WOT pull which I never do) and I still get a slight crunch from 1st to 2nd, and 5th to 6th (most noticeable)

I am wondering what my next step should be, becuase I know there is still room for improvement, and a modified CMC and/or adjusted pedal seems like the most sensible next step. Should I also look into a better fluid that wont leave me with the 1st gear lockout?

Sponsored