85 gs, 135k. Stock drivetrain.

When starting from a dead stop (or pretty much anytime under 5 mph) I have a rattling type noise, when the transmission is in gear. No slipping or any noises any other time, but its rpm related as well.

if im sitting in the parking lot, with the car in neutral and leave the clutch engaged (idling), I blip the throttle a touch and it makes this noise as well. If I hit the clutch pedal and disengage it....it does not make the noise.

I also get a shuddering when I engage the clutch from a stop....but only if I don't rev it up enough. If I do it just right, I can avoid the noise and shuddering but I don't know how long this will last. Hopefully I described this well enough

 

Sounds like a pilot bearing or throwout bearing needs replacing.

 

It will either last forever like that, or fail tomorrow. I drove one like that for about 30,000 miles and it never failed. If your clutch is fairly old, then I would wait until it was ready for replacement, and address the other items at that time.

Good luck.




.

 

A failing throwout bearing can eat into the spring fingers of your pressure plate. This process happens faster on a strong pressure plate. You could drive it like this for a while but it gets risky the longer you wait.

 

Good news is the clutch is cheap and easy to fix with a few hours.

 

Sounds like a throwout bearing to me too. Replace it. I like exedy\daikin

 

I'm still learning my rex, but couldn't it be something as simple as a heat shield or loose exhaust hanger?

That would have been my first guess. I suspect everyone else here knows what they're talking about (look at post count) I was just curious why shield/hanger might not be the first obvious check.

 

The fact that the sound changes when he puts the clutch in/out is what points to the pilot bearing/throwout bearing.

Also, after re-reading the OP's post where it mentions shuddering when engaging the clutch, I will revise my opinion and say that you should replace the clutch when you can, rather than waiting for it to start slipping. That shuddering is a sign of other issues, like worn or scarred flywheel surface, oil contamination, or possibly the clutch itself could be in the process of disintegration... I would address it now rather than later.

 

To me it sounds like a classic case of pilot bearing failure. Clutch failure is normally
slipping under high torque loads like flooring it in 4th on the highway. Stuttering
and chattering usually are symptoms of contamination from oil or grease on the
friction surface.

My advise, pull it now before the pilot bearing becomes a fussed mess in the
eshaft and requires extra work to repair. While doing this replace the clutch and
pressure plate and have the fly wheel resurfaced by someone that can do it
right (meaning keeping the new surface and the pressure plate surface at the
right gap). Also replace the clutch master and slave cylinder, they probably need
it as well. Oh and replace the rear main oil seal, its cheap, easy to do and the
old one is probably seeping oil onto the flywheel.

If you do all this you won't have any clutch related issues for another 50K miles.

 

Be careful about who resurfaces the flywheel. I looked for weeks without success, then found a lightweight flywheel and went with that instead...

 

kentetsu, shuddering also can mean a bad tranny mount. I've seen a lot of them where rubber has separated from steel. I'll be throwing a competition in mine. http://www.racingbeat.com/RX7-1975-1...ate/12050.html

 

My guess is a throwout bearing. But, it sounds like the pilot bearing.(I've never had a pilot bearing problem so I have no idea)
But if it is the throwout bearing it should do the opposite, it should rattle when your foot is pressing the pedal down, and when it's in neutral and you're foot is off you won't hear any noise. This is common when using aftermarket clutches, I have a 5.5" Tilton Twin Disc and the current 7.25" Quarter Master Twin Disc in my DD and the throwout bearing rattle when the clutch is pressed has always been there, there's no avoiding it, but it's also not causing a problem. It might do this on a stock clutch eventfully, but I don't think it'd be an issue if the clutch works flawlessly.

 

Jeff,

Have you considered the route that I took? I am very happy with the solid bushings.

Ryan from Shook Motorsports ( http://shookmotorsports.com/node/25 )

If you remember, I did a full writeup on the installation, but it's at (cough) another forum...

 

I think I remember that. You machined some white plastic or something for the outer two studs. I'm happy with my outer two as they're the 81-83 type which seem to work better than the 84-85 redesign. A little planned obsolescence was snuck in methinks.

 

I have had a pilot bearing go bad and what it does is it binds the eshaft to the input
shaft so that shifts become hard to make because the clutch even tho disengaged
by pressing the pedal, has little to no affect because the input shaft keeps spinning
with a load and so the tranny is still engaged somewhat and causes shuddering and
eventually stalling out. When mine went I had to drive home 30 miles using only
second gear and no stopping, thankfully it was 2 a.m. in the morning and there
wasn't much traffic. It had some early warning signs like the OP describes but at
the time I had no clue. This was back in 1984, a year after I bought it.