Well, I haven't received much help anywhere on my car problem. I might as well try here.

I have a horrible grinding noise coming from the clutch as I depress the pedal. Last summer I had my t56 rebuilt and a Mcleod Street Twin with adj. master cylinder installed. Everything felt fine for the 1st few thousand miles.

But upon driving my car 400miles to Socal and back up to Sac with a bad oil pan leak, I ended up with this wicked grind.

Back in Socal, I had a shop check it out. They found the Clutch disk hub to be machined wrong and having play on my input shaft (a manufacturer prob, which Mcleod acknowledged and helped on). But I don't know if that was ever the real problem because after installing a corrected one, the noise eventually returned.

I adjusted my MC but the noise only went away partially and with the clutch pedal sitting 3" off the floor.

I was told to check my clutch fork for possible grinding on the pressure plates, which I've just checked---no wear patterns.

What can it possibly be? My clutch disks looked good (as told to me by the mech). I don't think it should be tranny related, but I don't know for sure. The car now jerks under low rpm in reverse and first.

 

Did this all start immediately after the oil leak? Does the clutch completely disengage? What was wrong with the hub?

Rich Krause

 

Thanks for replying Rich.

The oil pan gasket leak had been happening prior to the clutch problem. But the long 400mi drive down to SoCal and back up (3 months later) to Norcal I think is what made the leak become worse. I think that because, on the way back up (2nd trip), I had lost a lot of oil and it was slinging onto the exhaust, even to the rear of the car. After refilling the oil to return to SoCal (3rd trip), about 200 miles into the drive and with oil burning off of my exhaust, I went to stop at the gas station and this is when the horrendous grinding began.

As I pulled off the freeway and applied the brakes, the car began to rev high in rpms, and it was hard to put the car in gear. I was able to put it in gear but not without horrible grinding. Needless to say, I made it home the next couple hundred of miles and was able to drive it the next few days with the grind.

When I took it to the shop, the mech said the disks looked fine, the rear main seal did not leak. But he found the Mcleod hub to be machined wrong. The hub had a bit of loose play when fitted over the imput shaft. Both hub and shaft were damaged. Mcleod is located right here so they got involved kind of. They said there may have been a small batch out there that was made wrong. So they gave me a new hub, used the same plates since they were still good. The mech installed it. I returned home with the car, noticing a very slight grinding when depressing the clutch pedal. They said it was probably the disks wearing in and that it would go away. A few weeks later the grind came back in full.

Adjusting the master cylinder helped reduce the noise. But now the pedal sat only 3" off the floor. If I leave the car in first gear and turn it off, when I turn the car on again, the grinding will occur.

After a hundred miles or less, the car would now jerk under low rpm in first or reverse if I didn't have my foot on the gas. This led me to believe it had to be clutch related. I decided to check the clutch fork this past weekend for any grinding on the PP, but I don't see any wear signs.

This is where I'm left at. What could I possibly check now?

Thank you and sorry for the lengthy message,

Daniel

 

Does the grinding change from when the clutch is pedal is fully vs. partially depressed? If you start the engine with the transmission in neutral and your foot off the clutch pedal and there is grinding, the input shaft bearings may be bad or the input shaft may be bent. If you hear a noise that stops when the pedal is depressed (still in neutral) the problem is lack of lubrication at the fork and pivot. If the noise gets louder as you depress the clutch, the throwout bearing is the problem. The pilot bearing is the cause of a squealing noise if the sound changes as the clutch pedal is depressed or released. If you have oiled the clutch plates, they will grind/chatter only when the clutch is engaged and the transmission is in gear.

Rich

 

The grinding occurs when in the process of pushing the clutch pedal and for that split second that I let off the pedal and drive.

If I were to actually hold the pedal to the ground, it would continue to grind (like a badly slipping clutch I think) until I let off. My discs are fine though.

After adjusting the MC, only when the clutch pedal sat 3" or less from the floor (untouched) did I experience little to no grinding when depressed. But it would grind if the car was started in gear.

 

Throwout bearing?

Rich

 

If it's the throwout bearing, what would make it go bad so soon? I need to do a search on it. I am at the point of trying anything right now. The car is apart and I don't want to put it back until I solve the issue.

Daniel

 

Does it grind or give ya like a hummin noise? I bet either the rear main is leaking or the oil pan is bad enuff, that its getting on the PP and disk which when it hits the friction point it kinda makes that draging a chair over the floor type senario. i could be way wrong on this but i had a similar expierence.

 

See, that it was I was thinking too. The shop said that the rear main seal wasn't leaking though (despite the bad oil pan leak) but they mentioned nothing about oil getting on the disk or PP. They said that the discs looked fine.

It's definitely not a humming noise. It does sound like a 2 objects putting pressure against one another and sliding. But if it's something as obvious as oil getting all over the clutch, why wouldn't the shop mention that?

Ok, inside the front face of the tranny where it meets the clutch at the bellhousing, there is oil smudged everywhere but that's normal right? Please tell me if I'm wrong.

I will say this, oil is flung across the whole rear exhaust, crossmember, and tranny and tunnel, even kicking up to the rear spoiler.

 

The proximity of the problem and the major oil leak has me suspicious as well.

Rich

 

I will be sure to replace the oil pan gasket before this fricken car lays it feet back on the ground. If anyone can remember whether or not the tranny should have oil sludge on its inner walls, please let me know. Maybe what I see is leaking oil shooting up into the hole where the tranny shield and starter meet. Maybe that's just enough to get it onto the clutch. the front face of the clutch at the pressure plate doesn't look greasy though.

When last I drove it into the garage, the car began jerking in low rpm in reverse or first right after putting it in gear, as if the clutch wasn't holding.

 

make sure your fork is on all the way.. look at the face of the pp as well to see if anything is touching.. somthing in the hyd. i think...

 

Illusional- That was the last thing I checked for and the pp looks normal and the fork appears fine. I will recheck though.

 

Did you ever fix this?

 

No, not yet. I've been trying to save up money to send it to the shop. I'm really concerned with taking it to the right people who will actually find out the problem and not just charge me up the *** to only pull the tranny. I've been given many possibilities by you guys here and a couple other boards. I've hoped to narrow it down to a TO bearing problem or a flywheel that needs loctite.

I've barely driven it But I've left the pedal adjusted to the spot where I rarely get any grinding. I just feel unsafe about the pedal being set so low from the floor. I just know the prob isn't yet solved.

I promise to let everyone know in my threads if I ever get a definitive answer when fixed.