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I have a nice grinding noise that I believe is my throw out bearing. It happens right at the clutch bite point(about 1in out, not all the way in) especially when I start from a stop and I can feel the grind in the clutch pedal. Current setup is Z1 mild performance clutch, Z1 midweight flywheel, Koyo throw out bearing and pilot bushing. Whole setup has about 15k miles (2 years) since I did MT swap and about 135k on the tranny. Noise has been happening for about 500 miles. Do I need to buy a whole new kit so I can replace pressure plate or should it be okay, and should I buy a new throw out bearing sleeve? I cannot leave the car apart while waiting for parts, but I would like to not spend money unnecessarily. Thanks
I'd be really surprised if that TO bearing died in 15k miles. Do you shift to neutral at stoplights and release the clutch?
Personally I would just drop the tranny and inspect everything, regrease as needed. What grease did you use on the friction points like the input shaft, face of the TO bearing, clutch fork faces, etc. If it wasn't a moly grease it might be wear due to friction.
If you release the clutch very VERY slowly without giving it throttle does it still make noise at very low rpm. Basically just letting the car idle in gear.
Does it make this same sound if you release the clutch IN NEUTRAL.
I never hold the clutch at lights but I do downshift every time I’m stopping and I used axle grease if I remember correctly. Noise does happen even if let out slow but sometimes not right when I start the car, until I put a load through it then it will do it under any circumstance even slow or in neutral. Not sure about VERY slowly I’ll have to check tomorrow. I guess I will just need to pull the tranny and check but unfortunately it is my only car.
I have a feeling you're going to be pulling that transmission, whatever is making the noise should be pretty obvious and yes the TO bearing would be the primary culprit. However it almost always make the noise immediately upon touching the clutch pedal (this is when the bearing starts to spin) but your noise seems to only be happening the moment the pressure plate and clutch friction disc start to touch so that's got me a bit confused. Might be worth prying back the rubber boot on the shift fork and using a flexible illuminated borescope to just look for anything obvious. You can put the boot back on from outside the tranny, it's like a window into the soul of your car.
Personally, I wouldn't ever recommending downshifting. Brake pads are cheap, clutch replacement is not cheap. Wear out the cheap parts first. Obviously racetrack stuff is different and you'll shift to whatever gear you need to exit the corner then rev-match when you can.
When downshifting, do you rev match or do you just release the clutch and let nature take it's course? If you're not rev matching your downshifts by blipping the throttle then you probably DID kill the TO bearing. They're really not designed for that kind of abuse, a downshift should ALWAYS be rev matched. It doesn't need to be perfect but you definitely need to blip the throttle and at least make an attempt. Heel-toe if you're fancy, or just lift the brakes and do a quick blip if you're a commoner like myself.
If you end up taking the tranny off to do a TO bearing I would also strongly recommend picking up a little tub of Valvoline VV986 moly grease, it's the best I've found for lubricating all that stuff inside the bellhousing. Yes it's a lithium based moly grease as recommended in the FSM for that application. Hit the pivot ball on the clutch fork, and the two points on the clutch fork that touch the TO bearing carrier, the inside of the TO carrier where it rides on the input shaft, the entire length of the input shaft, some people say avoid the tip where it rides in the pilot bushing but I've never had issues.
I rev match when I downshift but it isn’t always perfect. The borescope is a great idea so I can see if the pressure plate fingers are damaged. I’ll report back probably in a couple weeks once I’ve pulled the tranny for the repairs
Also here is the beginning of the original video. Had to cut it for size but since you were asking about circumstances you can see in this cut it does a small grind, then nothing, then the first video starts where I had to blip the throttle to make it grind again. All of this was done sitting still in neutral, but it sounds much worse when driving because I to go through that region slowly when starting from a stop.
Yeah you're just going to have inspect it. You got the TO bearing from Z1 when you did the clutch correct? They use factory OEM TO bearings in their kit so I would be really surprised if it was bad after 15k miles.
Have you checked the fluid level in the trans lately? I doubt it's the issue and I'm sort of throwing darts at the wall right now to see if anything sticks. Quicker than pulling the tranny though
Yeah my kit is from Z1. The mild performance says the bearing is Koyo brand I don’t know if that’s what Nissan used or not. I’ll check the fluid too when I do the borescope
I think you’ve got it worse than me! My bike is just leaking oil and needs the calipers rebuilt. Once I get that handled I’ll get to the G. Kinda thinking I’m just going to order a new clutch kit and replace the whole thing. The time to cost ratio just seems worth it since I don’t have the luxury of a lift
@cleric670 Can I get away with leaving my res test pipes on? Maybe just remove the O2 sensors? Looks like it’ll clear to me, but I had my oem cats last time I did this
Technically yes you should be able to leave them on but I always take them off since it's only a couple more bolts. I always start the bellhousing bolts by hand though (like literally with my hand) and it's a really tight squeeze for me to get my arm up to those ones on the top with the cats/tp in place.
