Question: 1970 M20 Transmission questions. . .

[Bolisk]

So, I've noticed a few things with the M20 trans that I would like some input on.

First, with the car runing, but at a dead stop (i.e. breaks fully applied), the clutch petal fully depressed, and I want to shift from a forward gear to the reverse gear. . .in many occasions I cannot get the Revere gear to engage. . .I have to shift into second then into reverse. Same thing happens when I want to shift into first from reverse . . . sometimes I have to goto second before shifting into first. Is this normal for a 1970 M20. . .or do I have synchro problems?

Next, I have noticed that on occasion, when the car is at a dead stop (i.e. breaks fully applied), the clutch petal fully depressed, and I wan to shift from a forawad gear to reverse (without shifting into 2nd first), it sounds as if the gears are grinding!! It's almost as if the clutch did not disengage completely. Is that an accurate assessment? Is it adjustable? I am I looking at a trans rebuild?

Note: the car runs and shifts smoothly through all forward gears. Only have issues switching back and forth between forward and reverse.

Thanks,
-JR

 

[JohnZ]

Sounds like the clutch linkage needs to be adjusted - the procedure is in the Chassis Service Manual. DO NOT adjust it to get the engagement at a given pedal height off the floor. The adjustment is made to achieve free pedal travel of 1" to 1-1/4" between all the way up against the rubber bumper to the point where you feel resistance when depressing the pedal (which is where the face of the throwout bearing contacts the clutch fingers). If you don't have adequate pedal free play, you'll fry the throwout bearing.

 

[jrzvette]

Sounds like the clutch linkage needs to be adjusted - the procedure is in the Chassis Service Manual. DO NOT adjust it to get the engagement at a given pedal height off the floor. The adjustment is made to achieve free pedal travel of 1" to 1-1/4" between all the way up against the rubber bumper to the point where you feel resistance when depressing the pedal (which is where the face of the throwout bearing contacts the clutch fingers). If you don't have adequate pedal free play, you'll fry the throwout bearing.

There's a very good article about clutches in the May issue of "Corvette Enthusiast".

 

[6880 Mike]

There's a very good article about clutches in the May issue of "Corvette Enthusiast".

Yep. Excellent stuff. You can thank JohnZ for that.

 

[Bolisk]

Thanks!!!

 

[JohnZ]

There's a very good article about clutches in the May issue of "Corvette Enthusiast".

Thanks - I wrote it.