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Discussion Starter · #1 ·
Couldn't find a good exact answer to this... I am having an odd clunking/rattle noise on my Muncie when I decelerate lightly. Seems to be mostly in 4th gear when I'm lightly deceleration. No problem accelerating or decelerating with pedal completely released. The noise can also be felt through the clutch pedal and floor. The output shaft has a little bit of play, not sure how much it should have. I also feel it just as I release the clutch into 4th gear, as the transmission catches up to the engine and driveshaft speed. Thoughts?
 

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slight rattling in the transmission COULD be the reverse sliding gear wobbling around on its splines

However; you indicate you can feel pulsation through the clutch pedal? If this is the case, I'd look at your clutch assembly. Do you by chance have a Centerforce I or II clutch kit?

Nathan
 

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Discussion Starter · #3 ·
I do have a center force in it. Not sure if it’s a 1 or 2. Hard to pinpoint if it’s from the clutch or transmission.
 

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Do yourself a favor, google search for problems with Centerforce I and Centerforce II.

A lot of people have complaints; some of which are completely bogus.

Centerforce's 'weight ring' that they add to a stock clutch, is fairly exposed. You have a couple dozen little 'flyweights' on pivots. These pivots get corroded and now the flyweights don't pivot in concert. This can give you a really odd vibration that comes and goes, even changes over time as weights get stuck/start moving/don't move as much as their neighbor.
Being in the Northeast, we seem to see more of this; I suspect that parking our cars for half the year, and wild humidity swings, corrodes things more quickly.
 

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Discussion Starter · #5 ·
That is a good point. The only reason I am leaning a little away from that is that this isn’t so much a vibration as it is a “clunking” or feeling that a loose or wearing out bearing would make. Want to narrow down the best I can before having to pull the transmission. Any bearings or bushings that are known to wear out?
 

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If you're getting pulsing through the pedal, I'm 98% certain its not in the gearbox, unless theres teeth coming off gears.
A bent mainshaft or input would be present in all gears, I don't THINK a bad input bearing would vibrate enough to feedback through the pedal either.
Reverse gears do oscillate on their splines, and you could certainly pick up the noise in low load 4th. GM even put a little spring in a pocket, under the gear to exert pressure on it and keep it from wobbling and making noise. But, thats at the other end of the output shaft from 4th gear, I doubt its vibrating hard enough to move the input enough to FEEL it.

Pilot Bushing could be bad, but that could also be symptomatic of the clutch hammering things.

Id get a fiberoptic camera if you dont have a big inspection cover on the bellhousing; and see what you can see. If the weights look rusty, if you see evidence of the disc losing material...its gotta come apart.
 

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Clunking?

Well thats possibly different.
Bad U-joint, driveshaft too long, bad front case bearing, clutch linkage and fork not in good shape...often clunk

Start at square 1:

Tell us about your car. Whats new, whats old, whats not OEM.
 

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Discussion Starter · #8 ·
Car is a 1968 Camaro SS, had it for 9 years. Put a 383 in it about a year and a half ago. Other than more power, drives just like it did with the 350 before it. When I swapped the engine I also put in a new clutch plate but kept the same pressure plate. For a year and a half it has been fine. I checked universal joints, both are good, no play. Where the yoke from the drive shaft goes in the output of the transmission feels like there is a little bit of play. Nothing major, not sure how much is supposed to be there. I’d have to measure for a definite response to you on that.

As far as the noise/feel, vibration is not the right word, more of a chatter... at about 20 htz.

It seems I am only feeling it in 4th gear, around 2,000 RPM, and in a light decel (as if you were going from a 55 MPH to a 50 MPH zone and lightly letting off the throttle). Full decal and any accel you don’t feel it at all. Push the clutch in and there’s nothing. I am trying to think of anything else that I can add to help. As far as changes recently to the car and/or power train, there is nothing.
 
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