06 Cobalt SS, 5-speed, N/A, 81k miles. I just purchased this vehicle yesterday. I was told that it had a recent clutch job, but have no type of verification. I got on it this evening from 1st to 2nd. After shifting into 3rd I let out and the transmission started making a loud chattering noise and the rpm's hung around 1500 for a few seconds. Idle is fine now but is still chattering. In the video the first revs are without the clutch engaged, the second 2 revs are with the clutch engaged (there is no difference, just thought I would mention). My thoughts are throw out bearing, but I would like some back-up before pulling out this transmission.

http://vid526.photobucket.com/albums...S/MAH00815.mp4

 

Any opinions on the issue? I was driving it today and noticed that if I'm sitting still idling and press the clutch, the noise gets a lot more quite. I'm planing on pulling the trans out soon. Another question, I read somewhere that you have to pull the engine out also if you're dropping it out of the bottom, AKA no engine hoist. Is this true?? I'd rather not go that route. Does anybody know if I can just remove the trans by itself from the bottom?

 

Loose flywheel bolts. I bet they re-used the old ones.

If not that, input shaft bearing.

 

I believe you are correct. Drove it to school tonight and the noise got worse. I'm on my way home, in 5th gear, and the just free rev's and I lost the clutch pedal. I pumped it and it came back but the car would still rev while in gear unless I gave it just a little gas. I pulled over and shut it off and now it wont crank back up. All I hear is the starter spinning freely, not making contact with the flywheel.
So can I pull just the trans out of the bottom without having to remove the engine? It looks like it would be an extremely tight fit with that crossmember in place

 

That doesn't sound like input shaft bearing. I'd check bolts and flywheel.

 

Im having it towed today. Im pretty certain it is the flywheel. Can anybody answer my removal question?

 

You need to remove the subframe brace before you can take the trans out.

 

Ok. That wont make me have to remove the engine, correct?

 

No just support it with a jack an zip tie the radiator up to the core support

 

Weeeeellllllll.. I pull the trans and the flywheel and clutch came out with the transmission.. All the flywheel bolts are broken off in the crank. I'm sure they are stronger then most bolts. Is it possible to tap them out?

 

Im sure you can tap them out but damn crazy that they even snapped

 

Sucks you had to bite the dust on this one. Let this be a lesson to others in the future, GET NEW FLYWHEEL BOLTS!

Here's a trick I picked up which may help you: take a punch and place it slightly off axis as close to the bolt hole as possible (while staying on the bolt), then use a hammer and repeatedly tap the punch to push the bolt around the axis. The combination of shock and torque from the punch may dislodged the bolt enough for you to get it out.

 

Yes, hopefully people will learn from my misfortune.
I will definitely give that a shot. I'm hoping that the cause was due to not even torque when they were tightened. Either way though, they should be fairly easy to remove since the threads are already stretched, right?

 

I hope in your misfortune that they neglected to use thread locker as well otherwise that will really suck.

I would also be careful with the use of heat. I don't think the crank will tolerate much.

 

The car is back together now. Drove it around this afternoon for a few minutes and went back home. Went to drive it an hour later, cranked the up and the rattling was back.. I replaced the bolts with Grade 8 bolts from the parts store and used blue thread lock as well. Torqued them down of course.
Is it absolutely necessary to use OEM flywheel bolts or is something crazy going on here? Also, does anybody happen to know the thread pitch for the flywheel bolts?

 

Flywheels can warp ..and you should of got the correct bolts from gm ...but most likely the flywheel is warped...or is it your throw out bearing now? If you take out your trans again and if the bolts are broke again lay a flat bar on the contact surface of the flywheel ..you should be able to see if it's warped if not use feeler gauges under the flat bar..or find a real flat surface to lay the flywheel on...also check where the flywheel meets the crank might have some thing going on there ..hope this helps.

 

Wow.

You absolutely need to use OEM bolts.

 

This for sure!!!

 

Ill be pulling the transmission again this weekend. I'm going to see what happened before doing anything. It seems like a flywheel issue. I used good bolts with loctite and went just above tq spec. But I will use the correct bolts. ARP or OEM?

 

OEM OEM OEM. Hit up CED

 

I'm going to get a new oem flywheel and bolts. Hopefully that will fix the issue.

 

Check the flywheel good or ill be pulling the trans a third time.

 

I will definitely check it over well. I'm not looking forward to a second time, let alone a third.

 

If you have a caliper check for run out before you start spending in a new flywheel to make sure that is your problem. Also yeah use oem bolts and torque to specs not above/less than specs

 

did you pull the trans again?