3rd gear knock updated 5/28

I have had similar experiences with V8 tranneys, and they were almost always caused by meshing issues between the input gear and 3rd cluster gear. It is amazing how much noise can be made by the smallest of meshing issues. Your results of propping up the rear, and carefully feathering the clutch while exploring the sound source with a mechanics stethoscope will be very helpfully in finding the loudest location of the noise. That followed with a very close inspection with the shift tower removed looking for the smallest of abnormalities on the input gear and third cluster should be very helpfully. I am inclined to lean toward the transmission, but I, for your sake, hope I am wrong.
Hang in there, we have all had these most frustrating experiences, and the encouragement of others is what keeps us from going crazy. You will find the problem. I sure wish I could be there to help you out.
 
I looked at a transmission without the shifter top and don't see any way the second third slider could interfere with the front gear on the cluster. I pressed it as hard forward as possible with a pry bar and got no interference. I believe I would try another ****** and find out if it is in the ****** or rear or motor. If you try this and the noise is gone you know where to look. If it is still there, it is in the motor. Lots of work but you will know what is making the noise.

As for the whine, I have built many Model A trannys and none ever sounded like that. The one in my Cabbie is quiet in all gears. The whine may be part of the knocking noise because of the gear speed. I have run lathes with straight gears that don't sound that bad and they get lots of abuse.
 
Kevin,

Now at office, with different computer, wonderful You-Tube-Video noise sounds more like a clattering than a grinding.

If you did not have time to try this former May 12, 2012 message # 15 test, may be helpful with less other conflicting noises:

"Maybe try this to simulate exact conditions:

1. Again remove bell housing inspection plate & remove (4) spark plugs.

2. Jack up one rear wheel & insert a very secure jack stand under the axle housing.

3. Place transmission in 3rd gear, & crank engine while looking through inspection plate hole with flash light."

Making a video of a more silent starter rotating the drive train may help.

As you have witnessed thus far, you have gained a lot of very concerned, compassionate friends, all trying to assist -- it has to get fixed with this many concerned friends.
 
Sure sounds like flywheel scraping on something too close like a starter bolt. Could be too much crank end play, you are pushing the crankshaft forward when you step on the clutch.
 
RichPA said:
Sure sounds like flywheel scraping on something too close like a starter bolt. Could be too much crank end play, you are pushing the crankshaft forward when you step on the clutch.
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My thoughts exactly!
The only problem is that it only does it in third gear with the clutch RELEASED. That's what makes this so perplexing.:confused:
 
RichPA said:
Sure sounds like flywheel scraping on something too close like a starter bolt. Could be too much crank end play, you are pushing the crankshaft forward when you step on the clutch.
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Would it not do this in 1st, 2nd, and 3rd? Sounds more like gears meshing or not aligned properly than a knock.
 
RichPA said:
Sure sounds like flywheel scraping on something too close like a starter bolt. Could be too much crank end play, you are pushing the crankshaft forward when you step on the clutch.
Click to expand...
If it were a starter bolt, pushing the clutch in would make the noise worse because the starter bolts are in front of the flywheel.
 
Were the clutch fingers looked at and height (length) verified? How much clutch free play? Is the thro out brg moving away from the fingers? Is it a std or lightened flywheel? V8 clutch and p/plate? Domestic or off shore cl and p/plate?
Paul in CT
 
It looks like the throw out bearing is still spinning. Could it be that the throw out bearing is bouncing against the fingers causing that sound.
 
I would try adjusting the free play for the throw out bearing! I had a similar noise but turned out to be the front shaft had a lot of play in it
 
The T-O brg is still turning when the clutch is released-Adjust linkage for an inch free play at pedal.Also,T-O brg appears to be jumping aroud a bit.Are the fingers adjusted so they are all 5/8" below P P rear surface?Was the T-O brg replaced?
 
bogdonj said:
I would try adjusting the free play for the throw out bearing! I had a similar noise but turned out to be the front shaft had a lot of play in it
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So you are saying adjust the clutch? The pedal has about 1" of play before it starts to move the throwout bearing. Is this normal? The bearing is close to the fingers before it does move, but I'm not sure it's touching them. I know it's not suppose to be touching...
 
Kevin at this point I would adjust the clutch and see what you get. It's a lot easier than pulling the ****** again.
 
Kevin - Illinois said:
So you are saying adjust the clutch? The pedal has about 1" of play before it starts to move the throwout bearing. Is this normal? The bearing is close to the fingers before it does move, but I'm not sure it's touching them. I know it's not suppose to be touching...
Click to expand...

The throwout bearing should start moving forward as soon as the clutch pedal starts moving, but the throwout bearing shouldn't touch the 6 fingers until you've moved the clutch pedal down about 1", which is the FREEPLAY.

I couldn't see your left foot, but were you riding the clutch?
 
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Kevin, it almost sounds as if there is one bolt going into the trans somewhere that is to long and is making contact when in third gear. Don't really see how but that's what it sounds like. Plus, if you leave it in neutral and start it, does the throw out bearing spin? It should not.
 
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