Clutch shudder

[Baker7888]

I wouldn't think so, unless if the spring you are using is substantially softer than stock. You want to be sure the throwout bearing isn't contacting the pressure plate fingers when the pedal is all the way up or it won't last long. The throwout bearing is meant to "run" only when the pedal is depressed. If it's running all the time, it will wear out very quickly and will start screaming. Then you're pulling the transmission to replace the throwout bearing.

Regarding the leaks....Those old 4-speeds are pretty easy to work on. No internal disassembly is required to address leaks. Make sure your speedometer drive isn't leaking. Beyond that, it's just gaskets and seals. Also thread sealant (not RTV) is advisable on the bolts that go right into the case where the oil is present.

Are you sure it's the transmission that is leaking? Oil on the clutch disk can cause chatter.

Thanks. Yes transmission is leaking. I keep an eye on it via a piece of cardboard on the garage floor. There was some oil present in the bellhousing at one point. I dont believe it to be getting on the clutch but i am not certain about that. I will see if it’s still present when i get under the car at some point this weekend. I know I cut a gasket for the input shaft cover. I know it has a drain that should not be covered. I was aware of this at the time. I dont remember all the details on that but was getting conflicting info about it at the time. This was last winter and my memory is a little foggy.

Anyhow most of the leaking appears to be coming from a roll pin at the bottom of the transmission. All other bolts i have sealed with aircraft thread sealant. I also replaced tailshaft seal cause it got chewed some how. I had transmission shop “inspect” transmission before install, they said it looked excellent. Knowing i was on a budget he basically just popped the cover and looked inside and said nothing warranted further investigation. If i floor it down a stretch say, i get a good amount of stick vibration. Not sure how much is normal. I know this is antiquated technology and i dont expect it to behave like a Japanese 5 speed but would still like to work out some of the kinks

 

[Built6spdMCSS]

Hmm. Well that had been my suspicion all along. Didnt bother me until a bystander thought it was engine knock. Kind of embarrassing at the moment. I guess i’ll look to see if the throwout has contact and if not i might move on. I do want to pull the transmission at some point but can also live with it as is.

It must be pretty damn loud then, mine is a very distinct chatter you have to listen for over the exhaust of the car. I hear it because I know what I'm listening for.

 

[Baker7888]

It must be pretty damn loud then, mine is a very distinct chatter you have to listen for over the exhaust of the car. I hear it because I know what I'm listening for.

It’s not super loud but you can hear it, usually when the car is cold if i’m not there to babysit the throttle it will idle pretty damn low. I work with the guy and he was probably hunting for an imperfection, last few minutes before punching out I had it warming up while I was inside. 3 sides of metal buildings in a small 8-10 car parking lot probably helped it resonate.

 

[Built6spdMCSS]

Yea mine literally sounds like marbles in a can, just normal clutch chatter. Been that way for over 4 years and I've driven several cars with the same clutch so it's normal.

 

[Bonnewagon]

Chatter or vibration has several causes, most have been addressed above. On the clutch disc is a mechanism called a Marcel, which is the slim spring metal plates sandwiched between the facings. Then there are the springs arranged in a circle around the hub. Those are there to absorb the shock of clutch engagement. If you have a 'racing' type clutch, those things may be missing. I prefer a diaphragm type street clutch for smooth engagements. As for popping out of gear, the brass synchronizers can be worn out. You cannot tell by just eyeballing them. It requires complete dis-assembly to change them out so might as well do the seals while in there. Jumping out of gear, and leaks, would indicate to me that the 'rebuild' was a very long time ago, or botched. Does it shift smoothly? Or clash a little?

 

[Baker7888]

Chatter or vibration has several causes, most have been addressed above. On the clutch disc is a mechanism called a Marcel, which is the slim spring metal plates sandwiched between the facings. Then there are the springs arranged in a circle around the hub. Those are there to absorb the shock of clutch engagement. If you have a 'racing' type clutch, those things may be missing. I prefer a diaphragm type street clutch for smooth engagements. As for popping out of gear, the brass synchronizers can be worn out. You cannot tell by just eyeballing them. It requires complete dis-assembly to change them out so might as well do the seals while in there. Jumping out of gear, and leaks, would indicate to me that the 'rebuild' was a very long time ago, or botched. Does it shift smoothly? Or clash a little?

Thanks Bonnewagon. It does shift smoothly.

 

[Bonnewagon]

My first four speed Saginaw was from a junkyard known as 'Cheap Mike's'. It jumped out of gear. After taking it back a couple of times and nothing being done to correct it [Cheap Mike was well named], I bought a small parts kit and successfully re-built it myself. Over the years I learned to actually measure the brass synchronizer rings before changing them out. A few thousandths is all it takes to act up. What they do is slow down the gear assemblies so that they are going the same speed. That allows the gears to change. Once engaged, the synchronizers, sliders and gears stay put. If worn, they can slip apart. If your shifter is not adjusted correctly, it will pull the gears apart and 'jump out' of gear. Is it a Hurst shifter? They have stops that need to be adjusted properly. Read this, it's for a Muncie, but similar. https://www.chevydiy.com/muncie-4-speeds-work/

 

[Rt Jam]

How much you press the clutch pedal to make the noise go away will determine where it's coming from.

If you have clearance between the throw out bearing and the pressure plate fingers. Just lightly pressing the clutch pedal, takes up that slack. Then the noise goes away. That is the throw out bearing rattle around then goes quite as it spins the speed of the pressure plate.

If you go deep into the pedal, like half way or to the floor to stop the noise. That is the transmission. It turns with the engine when the clutch is out. Then it stops with the pedal to the floor. That is normal for a box of gears to make some noise when it's turning. How much noise is not for me to determine.

The shuddering is hard to assess in non stock applications. The hub springs are meant to fight engine oscillations. Finding the correct hub springs number and strength is a big ordeal. Marcel was mentioned, it should also help but they are not in racing clutches and the disc material may not be smooth due to it's racing nature.

 

[Bonnewagon]

I also once had a pressure plate that was defective. In the bolted-down position, several of the Belleville spring fingers stood up higher than the rest. Even with the linkage adjusted, every time those fingers came around they banged against the throwout bearing causing it to spin. It was so bad it made the clutch pedal vibrate. It took a new unit to correct that.

 

[Baker7888]

Remove the clutch inspection cover and visually verify that the throwout (clutch release) bearing isn't touching the pressure plate fingers

What inspection cover exactly are you talking about ??? Had to get under the car but I am using a G body bell housing and there is no cover. Removed fork boot but not enough room to see …