Clutch Diagnosis

U

ursus

Well-known member
Trying to sort out a problem that seems like the clutch is dragging on a newly rebuilt engine. The clutch plate is new and the pressure plate is rebuilt and balanced with a resurfaced flywheel. The flywheel surface run-out is 0.002" and the flywheel housing run-out is 0.004". Pressure plate fingers were all adjusted to 11/16".

My question is this: with the clutch pedal fully depressed, gears in neutral, and the shifter top off the transmission I should be able to rotate the transmission main shaft by hand, correct? With the clutch pedal up (engaged) should I be able to rotate the main shaft? Thanks all!
 
The clutch plate is slightly dished so that the clutch engages smoothly. That may be part of the problem. But if the fingers are not adjusted exactly the same, part of the pressure plate will disengage while another part stays engaged. That may be the problem. I think the specification on the fingers is withing 0.002 of each other. Another possible reason is that the clutch peddle is not adjusted correctly. You should have 1 inch free play at the top but no more.

With the clutch peddle to the floor, and the transmission in neutral, the main shaft should be able to rotate. With the clutch engaged (clutch peddle up) you should not be able to rotate the main shaft.
 
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" With the clutch pedal up (engaged) should I be able to rotate the main shaft?"
I say no since the main shaft is connected to the driveshaft.
 
I decided to double check by looking at the exploded diagram of the transmission.

Did you use the correct name for the component? The "main shaft" is at the rear of the transmission (part #43 as per drawing) and the "main drive gear" is at the front (part #6 as per drawing).

If transmission is in neutral, the clutch peddle is up/engaged, the main drive gear at the front of the transmission will try to turn the engine. Clutch peddle down / disengaged, transmission in neutral, the "main drive gear will turn the cluster and a free spinning clutch disk only.

With the transmission in neutral, if the transmission is not attached to the driveshaft, as in, the transmission is not in the car, then the cluster is not meshed to the main shaft and the main shaft could be turned by hand.
 
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