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Clutch chatter

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Old 05-17-18, 07:37 PM
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Clutch chatter

Have not driven the car in 3 weeks and drove it to Costco and back (5miles). From a dead stop, clutch chatter is unbearable unless you give it about 2500 rpm. This just started, nothing new or changed other than sitting. Clutch fluid level is fine, I changed the master about a year ago. It's the original clutch, based on all the PO hack jobs, it may be worn out, but no slipping, once I get going all shifts are fine and pulls strong.

Could an oil leak from the back of the engine contaminate it? Nothing leaking, so just grasping at straws. 85 GS, all stock with 65k on the clock. Unfortunately all my real tools are at my new house 300 miles away and hate to pay someone to tear into it. Thanks
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Old 05-17-18, 08:30 PM
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Sure its not old motor/tranny mounts?
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Old 05-17-18, 08:48 PM
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Both are new oem mounts for motor and same for transmission. I'll get it up on stands this weekend, had not thought to check them out, thanks.
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Old 05-18-18, 01:22 AM
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When you describe 'chatter', are you feeling that through vibrations on the shifter, or through the clutch pedal, or somewhere else? Typically, chatter is when the input shaft of the transmission isn't centered in the middle of the eccentric shaft, allowing for wobble when you engage the clutch. Normally, that's not a problem if a Pilot Bearing is missing, as spinning parts tend to center themselves once they're connected, anyway. I've run my -SE without a Pilot Bearing (it grenaded) and you couldn't really tell it wasn't there...

Point being, the chatter you may be feeling at the shifter could actually be your Transmission Mount, or one of the bolts came loose, or the rubber isolater has given out. That usually allows enough play at the rare of the transmission that any vibrations during clutch engagement would be magnified. You said you replaced that already, but a missing mount bolt might feel like that.

It's unlikely to be any kind of lubricant leak that got onto the pressure plate or clutch disk. The flywheel and/or counterweight protect the front of the clutch facing the engine from any contaminants, so the only place it might be leaked lubricant would be the Transmission Front Seal, and those are rarely a problem.

If you're feeling it through the clutch pedal, it could also be a bad Throw-Out Bearing, as that's directly connected to the clutch hydraulics through the TOB Fork, and if the bearing has gone out, you could feel that through the pedal, and it would make a hell of a racket when spun up - but NOT when clutch is engaged, as at that point the TOB is not under load to separate the Clutch Cover from the Pressure Plate. It's a cheap part, but once you can get to it, you might as well do the full routine Clutch service...

Hoping for the best - and report back once you get it apart,
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Old 05-18-18, 05:35 AM
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Thanks, it's hard to tell where I feel it most, it's fairly violent, but would see more in the shifter. All screws/bolts etc are tight in the driveline, but will check out the rubber on the mount tonight.
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Old 05-18-18, 04:31 PM
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Back to square one... no slop in motor or trans mounts. Ujoints have minimal and no excessive wear. Gonna be super mad if I have to get someone to tear into this, I hate paying for things I can do myself. I'll drive it around tomorrow when no traffic to see if I can deduce anything else. I appreciate the input so far. If a get a clutch I'm thinking Exedy close to oem. Never gonna be a track car and will just use for cruising and commuting. Thoughts on a basic unit vs stage 1 or something else?
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Old 05-19-18, 05:52 AM
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I'm very interested in your diagnosis, I have a similar issue but it sounds like yours shudders much more than mine at this point...LongDuck's thoughts are very interesting.

There was this thread where tg is querying about the next clutch to buy: https://www.rx7club.com/1st-generati...there-1123053/ (although I see you were on that thread).
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Old 05-19-18, 10:07 AM
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I was following TG's post as well, but he drives a little more aggressively than I do, so I don't need a higher end unit since I really need stop and go traffic ease of use.
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Old 05-21-18, 10:22 AM
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I have the stock Exedy from RA installed and beat the living $%^& out of it at DGRR and no issues, no slipping or chatter.

You may want to check out the slave cylinder and see of its pushing all the way on the fork, otherwise the clutch may stay engaged slightly and cause issues like this. It could be beginnings of the pilot bearing going as well. Did you try pumping the clutch a few times before starting out? If that helps its just the slave cylinder.
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Old 05-21-18, 05:26 PM
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The slave is newish, 8 months or so and just checked it and seems to be working. I know the pilot bearing makes a little noise when in neutral and clutch pedal is out.
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Old 05-22-18, 07:18 AM
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Originally Posted by Ckforker View Post
The slave is newish, 8 months or so and just checked it and seems to be working. I know the pilot bearing makes a little noise when in neutral and clutch pedal is out.
By clutch out you mean foot off the clutch? If the clutch is engaged (foot off the pedal) then the pilot bearing is not in play and the noises are coming from the tranny or throwout bearing. I would double check the ujoints as a frozen or stiff one can cause this sometimes. I know because that was the cause of my driveline vibration issues recently. The front ujoint was binding because one of the bearings had returned to earth and was just a bunch of dust.

If you need help with this txt me and we can talk about it. I know you have limited resources down here now.

Last edited by t_g_farrell; 05-22-18 at 09:02 AM.
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