Squealing When in Neutral

[pagrunt]

There's too much play there. As 64nailhead said with adjusting the rod or you may need a longer throw out bearing (longer measured from where the plate fingers contact the bearing towards the transmission). Most likely get the pedal play to GM's spec things should be quieter.

 

[Built6spdMCSS]

Yea too bad you can't shim the Bearing like on some stuff.

 

[ELCAM]

The arm is way too loose. It sounds like the arm is hitting the side of the pressure plate is what the noise is.

Going to guess the spring for the pivot ball is in front of the pivot and not behind it like it should be making the arm too far forward allowing the interference you have and creating all the looseness in the arm.

I suppose the arm could also be behind the throwout bearing instead of in the groove for it. That would also misalign the system and cause the same problems.

 

[Full Garage]

Built6spdMCSS - This particular t.o. bearing had an anti-rotation tab built into the groove where the fork fingers go, so no rotation possible. The previous (2) did not have this featureDefinitely agree that it could be scuffing the pressure plate fingers.

64nailhead - Can't hurt to go through the process from the very beginning. I've obviously missed something along the way. I certainly have "a few spare parts" :^) its just that little things like this squeal drive me crazy, especially when I know its not normal.

ELCAM - The clutch fork hitting the pressure plate is not something I've thought about. Not sure how to diagnose that one, but certainly worth investigating. I know that the pivot ball is captured by the spring and that the clutch fork fingers are in the correct location; I made that error once already and learned the lesson.

Is there a possibility that the spring holding the fork to the pivot ball is "sprung" or loose, causing the fork to move around more than intended?

 

[ELCAM]

The spring can be bent enough not to work. Pic is an NOS clutch fork for a G body I found on line, shows how tight the spring is.

Loosen the jam nuts on the lower linkage, remove the spring from the clutch fork. Push the fork in by hand till the throw out bearing is contacting the pressure plate diaphragm. Adjust the push rod till there is a 1/8" gap between the push rod and the fork while keeping the throw out bearing in contact with the pressure plate diaphragm.

Tighten the jam nuts and reattach the spring. See if it makes noise.

 

[Full Garage]

Good morning, and a big "thank you" to all that have commented. I have a new clutch fork on order which should be here next week. It seems to me that it is a bit loose when it is sitting on the pivot ball. I may be wrong about this, but there's 120k miles of use, so I figure it can hurt to install a new one. That will also ensure that the clutch adjustment is as correct as possible. I'll update as soon as I get everything put back together and adjusted. Happy Holidays!!

 

[Kra5379]

I have a 79 Grand Am with a 301 and factory 4 speed (Saginaw). My problem is there is a drivetrain squeal when the car is idling in neutral, or being driven down the road. It sounds like a belt squeal, but here's the weird part; as soon as I press the clutch pedal in a 1/4" the squeal goes away.

Things I've done:
1. The transmission has been rebuilt by a reputable shop in my area.
2. I've tried 3 new clutch assemblies, the last of which has an SKF throw out bearing.
3. The pilot bearing is a rolling element design, moves freely, and has been lubricated.
4. Followed the instructions in the factory service manual for adjusting the clutch linkage and pedal travel.

Any thoughts on my next step?

Sounds like possibly a bad input shaft bearing or reverse idler gear, something internal to the transmission. A bad throw out bearing would act just the opposite, it would be quiet at idle/in neutral, and there would be noise when pushing the clutch in

 

[Full Garage]

Kra5379, thank you for your thoughts. I did have the transmission rebuilt last year, but after 3 different throw bearings, you may be correct. I received the new clutch fork over the weekend, so when I go to install it I'll have the transmission out on the bench. I'm thinking of a way to spin the input shaft while it's out to see if the transmission squeals. I'll post something after the "test".

 

[Built6spdMCSS]

So we are back to page 2 of this...

Have you tried spinning the input shaft of the Transmission by hand to see how tight it is? If the squeal is the same when in neutral and in gear, and only changing when the Clutch goes in, I'm leaning toward the Input & Mainshaft being too tight and it's loading the bearings.

I know you said it's in neutral, the "being driven down the road" part makes me think you had it in gear, or is that rolling in neutral at speed and it's still making noise.

Is this something that started randomly or when you put the Transmission back in the car?

Built6spdMCSS - I did check that and in fact the input shaft is a bit loose, ~0.004" of radial play, which could be a problem. Although the shop that rebuilt the transmission said it wasn't a problem (perhaps some/ alot of BS there?).

The squeal occurs in neutral and any gear. If i depress the clutch pedal the noise stops. So if I'm driving down the road, at speed in 4th, and I hear the noise, all I have to do to get it to stop squealing is just lightly rest my foot on the clutch pedal. Thanks.

Try the new fork and adjustment, see what happens.

I'm thinking of a way to spin the input shaft while it's out to see if the transmission squeals. I'll post something after the "test".

Grab shaft, turn it. If the bearings are tight, you'll know.

 

[Full Garage]

Good evening. Here is a link to a video showing a test of my Saginaw

.https://youtube.com/watch?v=gNSlSWgNqgk&feature=share

The speed of the drill is 1600 rpm. The primary noise is the drill. I did hear some low frequency bearing noise, but no squealing.

Elcam - I looked at my old clutch fork, and the new one, and neither has the spring finger close to the arm. I'm going to focus on that tomorrow (hopefully).

I verified that the input shaft and front bearing carrier are properly lubricated with high temp brake grease. The throw out bearing spins freely.