Transmission grinding noise after CMAK install

rclarkbow

So my CMAK v2 csc relocation kit went on well, but now I've noticed there's a grinding noise sometimes from the transmission, only on cold starts and below 30 degrees f so far, and on and off even then.

It grinds when i start the car, let the clutch out in neutral, and push it in again, putting it into gear or not doesn't seem to make a difference, the clutch being pushed in is what causes it. The first time it happened there was a concerning metal on metal grind noise that was prolonged from the transmission.

Any ideas? I'm thinking throw out bearing, I believe the kit included a replacement. I had this done by a trusted mechanic, and haven't gone to them yet about it.

Transmission has been good so far, no grinding, but the car is at 120k miles. Wondering if this issue could be the trans itself.

Thanks

DOOMMONKEY777

Sounds like a bad alignment of that CSC, grinded synchronous or damaged transmission bearing, in any case

1) check for codes
2) change the transmission fluid to reline (75w80 i think for z34 check manual)
3) when you try to go in to 1st on cold days and it does not want to go in to 1st gear, do NOT force it, rather go in to 2nd then back in to 1st, this will eliminate hard entrance to 1st.

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rclarkbow

No issues getting into first on cold days. Had them replace the fluid with the redline brand synthetic when I got the CMAK installed. No grinds at all from the transmission itself, really the trans feels like butter.

I'm thinking misalignment of something or possibly aftermarket parts designed for the track and not the cold? Who knows, it's made it a couple of times since I posted but I'm thinking it's with the clutch / hydraulic system for the clutch. I'll update if I ever end up sorting it.

Joe@ZSpeed

Sounds like a pilot bushing making noise if it comes and goes. Was it changed? Did you get your old one back?

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Quicksilvers

+1 Sounds like a failed pilot bearing replace it as soon as possible if that is the case it will only get worse over time unfortunately.

rclarkbow

Thanks for your replies. I am going to inquire with my mechanic tomorrow about the pilot bearing / bushing replacement. I don't believe it was replaced when I first did the CMAK install.

Trans coming out yet again it looks like...sigh.

Thanks for info, good to hear from you, Joe, I love your product.

jchammond

Follow instructions on alignment of the cmak; there’s a particular way to tighten bolts & check for smooth operation.
Also be sure slave is properly bled....couldn’t imagine tech installation new clutch without replacing pilot bushing

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jchammond

Unsure the clutch you had installed; helped a buddy of mine do his...used a rethreader to clean up all bolts & holes from clutch,flywheel,crank & trans bell housing (very helpful)
Also old pilot bushing was slightly egged & used a flywheel holding tool to evenly pull up & torque new flywheel.
Another member suggested this/ as this could pose an issue if it’s not pulled up flush.
Afterwards ~ Tranny slid back in very easily,,,but we did have to tweak adjustment on cmak for smooth/even operation before assembly.

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B&W_Evader

Get the Nismo pilot bearing rather than the bushing. They're way better and only a couple bucks more. Only good thing about having a bushing is that it's easier to remove. Replace the throw-out bearing while your in there if it did not come with the CMAK. It's the one that pushes on the teeth of the pressure plate.

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Joe@ZSpeed

I recommend keeping the bronze OE bushing, You've evidently have never seen what the nismo pilot does to the input shaft when it goes bad. You can replace the bronze pilot or replace the pilot and input shaft if the "nismo" Needle bearing goes bad.....

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Shoeshear

Zspeed kit comes w/ bronze pilot bushing. If you got it done by a mechanic and you gave them the whole kit, they should have done it along w/ the other stuff. I also just got CMAK a month or two ago and don't have the grinding you describe. I do have increased clutch chatter at low RPM w/ relatively high loads in 1st or second, but expected from reduced flywheel weight, but I take it that's not what you're talking about?

rclarkbow

Thanks for all replies

Update:

Talked to mechanic, car is going in Thursday. Sounds like yes, the pilot bearing and the throw out bearing were both replaced as they came with the kit. So it's a mystery as of right now. I'll keep the thread updated for anyone who is interested.

Symptoms as of now:

1)Grinding noise as clutch is engaged or as it's being released (only when car is cold)

2)This morning (cold) there was a loud metal on metal "sloshing" noise coming from the transmission that went away after driving for 2 minutes.

Any ideas or brainstorming welcomed, thanks as always guys!

cthorson910

I'm planning on getting this cmak kit once my slave kills itself (knock on wood its still fine at 54k) and have watched the install videos a handful of times. Unless you've got bad luck and have bad parts out of the box, there is only 2 things I can think of that could be causing the noises. In part 4 of the install video, he mentions a little bit of grease on the inner diameter of the throwout bearing where it meets the tube on the front of the trans that goes around the input shaft, and also a specific tightening sequence to center the fork and throwout. My guess is that one of those 2 things (or both) weren't done properly.

rclarkbow

Mechanic stated that it was the throw out bearing making the noise. I'm not sure if something was misaligned by them or what.

I'm waiting a bit to fix it, they might help me out on the labor to take the transmission off again, I'm not sure.

Joe@ZSpeed

Throw out bearing noise will get louder the more you press on the clutch, If it is only making noise right before engagement/disengagement and goes away once clutch fully grabs it is the pilot bushing.

I guarantee the throw out bearing is not bad. It is a beast of a bearing.

I put my money on they did not change the pilot bushing and now it is making noise and they do not want to put what they should have done the first time in again for free.

If you hear a quiet "Zip" type noise with car off when pressing clutch in and out quickly this is normal as you can hear the bearing slide on the bearing guide tube esp if it is not lubed well. This goes away in time as the sleeve wears smooth in to the guide tube. If it is excessive they did not center the fork well as instructed in the instructions.

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