Help me Diagnose please!
 

Okay, well about maybe two months ago or so Ford had to rebuild my MT-82 transmission because gears 1-4 were messed up. They also claim to have replaced the input shaft bearing. Just before I had them perform the warranty work, I replaced the clutch and flywheel because I thought it was the original problem. I believe when the transmission grenaded, it blew the clutch.

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I replaced the clutch with a Spec Stage 2+ from Stage3motorsports and purchased the aluminum flywheel to match.

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Had a certified mechanic do the procedure who recommended also replacing the throw out bearing which I did. The car was making a noise after like a grinding noise when idle but disappeared when the clutch was pressed. Ford said it was the throw out bearing so the mechanic gave me yet another new throw out bearing in which Ford installed during the transmission rebuild.

So my issues is that the grinding noise is still present! Two throw out bearings and input shaft bearing later. I thought maybe the pilot bearing but the noise goes away when the clutch is pressed. It isn't something that is slight either. You can hear the noise from a good distance away from the car. It is embarrassing at stop lights.

I had Ford look at the car and they test drove it and said it could be the input shaft bearing or the throw out bearing. Only way to tell is to pull the transmission. If it is the input shaft then they will cover the cost, if not then it will cost me $400 just for them to pull the transmission. I am having the mechanic who did the clutch install look at it on Friday who is going to try and listen to the throw out bearing via the hydraulic line while the car is running in the air.

I am also curious if anyone else has a Spec clutch and Aluminum flywheel. From fast starts in first or starting in second I get a squealing noise which maybe it is just the clutch material? It is really loud. I did do a proper break in procedure for the clutch.

Is it like a marbles in a metal can sort of sound? Could be gear rollover, which sounds like that and will go away with the clutch pressed. An aluminum flywheel will greatly increase that sort of noise as well.

How do you like the light flywheel? I'm considering either a steel or aluminum one piece this spring.

I can't feel a huge difference but the mechanic said it felt a lot lighter. Yes it sounds like marbles in a metal can.

Yeah it's probably rollover noise. Lightwave single piece flywheels will amplify ANY noises the gearbox already made, and these are known for having decent rollover noise.

No free lunches and all that. Race cars aren't quiet and noise/vibration free for a reason. Lighter flywheel means increased performance and increased NVH.

Input shift bearing could also be the issue. It's difficult to tell for sure without looking. If you happen to be inside the gearbox again might be worthwhile to just replace it anyways.

I could understand a slight increase in NVH but I can hear it across a parking lot while the car is idling. I'm sure the Ghost cam tune isn't helping.

I hope someone with the aluminum flywheel will be able to comment if they have a similar issue.

I would think a bad throwout bearing wouldn't make noise when clutch is fully released, only when you depress it, which is the exact opposite of what you describe.

The more I investigate rollover noise or gear chatter, it seems to fit the symptoms I am having and it is directly caused by having a lightweight aluminum flywheel. I will have to the mechanic listen to it to confirm but I find that the noise is super loud for something that is going to create a slight increase in NVH.

It's not caused by the flywheel...the noise is there regardless. However dual mass flywheels do a pretty good job of stopping various gearbox noises from being heard, or at least quiet them significantly. I can still hear it quite well with my stock setup, and I'm sure when I eventually install a lightweight flywheel it'll get significantly worse.

It's just one of those things, like installing poly suspension bushings or motor mounts. Yes there are benefits, and the downside is usually more noise and vibration. It's the same thing with the flywheel. LW flywheels are well known for increasing transmission noises significantly.

What I meant was the noise was being caused by the aluminum flywheel. I know the noise might have always been there but I never heard a peep out of it before. I will still have the mechanic look at it to be sure but I wasn't expecting it to be this loud where I can hear it over my Roush exhaust. In the garage it is downright silly...

So I had two mechanics look at my car and it is determined that the noise is coming from the gear box. I mentioned if the aluminum flywheel would cause gear rollover noise etc. They said with the modern cars it should not be making any noise even with the aluminum flywheel. I also have my water pump leaking so off to Ford I go in the morning.