Broken Input Shaft Symptoms? - Chevelle Tech
Transmission & Driveline Transmissions and Differentials

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post #1 of 19 (permalink) Old Dec 20th, 18, 11:01 AM Thread Starter
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Broken Input Shaft Symptoms?

Morning TC. Last night I decided to take the car out for "one last drive" before winter shows up. I had been driving for about 10 minutes everything perfect as usual, no strange noises, vibrations, etc. Pulled up to a red light. When the light turned green I release the clutch and nothing but the engine revving from the gas I was giving. A passerby helped me push the car to the side of the road and noticed the clutch pedal felt "looser" like way easier to depress. Also, I am able to move the shifter through every gear incl reverse without the clutch. Looked under the car and all the linkages seem to be good. I had to get the car towed

Does that sound like an input shaft problem? The car is sitting at a shop, but I wanted to try and get a pre-diagnosis.

Thanks,

Rocky
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post #2 of 19 (permalink) Old Dec 20th, 18, 11:40 AM
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Hank
 
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Re: Broken Input Shaft Symptoms?

I would think more something to do with the linkage. It could be on either end of the Z-bar or even the return spring broke. Check the ball stud on the block it could have worked loose.

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post #3 of 19 (permalink) Old Dec 20th, 18, 1:06 PM Thread Starter
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Re: Broken Input Shaft Symptoms?

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Originally Posted by HKalin View Post
I would think more something to do with the linkage. It could be on either end of the Z-bar or even the return spring broke. Check the ball stud on the block it could have worked loose.
Roger that. Thank you.
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post #4 of 19 (permalink) Old Dec 20th, 18, 3:08 PM
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Re: Broken Input Shaft Symptoms?

If the clutch linkage failed it would have likely failed with the clutch engaged. You wouldn't be able to get it into and out of gear with the engine running. If the clutch pedal feels soft, I'd suspect the pressure plate failed in the disengaged position somehow or the linkage jammed somehow holding the clutch disengaged.

Is the shifter linkage still attached and working properly?

If the input shaft broke, I'd think you'd have heard some ugly noises.
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post #5 of 19 (permalink) Old Dec 20th, 18, 6:53 PM
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Re: Broken Input Shaft Symptoms?

Let us know what they find.

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post #6 of 19 (permalink) Old Dec 20th, 18, 8:14 PM
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Re: Broken Input Shaft Symptoms?

If you can step on the pedal with no resistance and the car doesn’t move I would guess the diaphragm of the clutch is over extended and the pressure plate is stuck.
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post #7 of 19 (permalink) Old Dec 20th, 18, 8:40 PM
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Quote:
Originally Posted by bracketchev1221 View Post
If you can step on the pedal with no resistance and the car doesn’t move I would guess the diaphragm of the clutch is over extended and the pressure plate is stuck.
This’ll be my guess.
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post #8 of 19 (permalink) Old Dec 21st, 18, 7:51 AM Thread Starter
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Re: Broken Input Shaft Symptoms?

Quote:
Originally Posted by Rich-L79 View Post
If the clutch linkage failed it would have likely failed with the clutch engaged. You wouldn't be able to get it into and out of gear with the engine running. If the clutch pedal feels soft, I'd suspect the pressure plate failed in the disengaged position somehow or the linkage jammed somehow holding the clutch disengaged.

Is the shifter linkage still attached and working properly?

If the input shaft broke, I'd think you'd have heard some ugly noises.
Thanks, yeah that was the thing...no ugly noises. Linkage is all in place, I had a buddy engage it while I looked under and above and it all appears to be working. Its just real soft.
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post #9 of 19 (permalink) Old Dec 21st, 18, 7:54 AM Thread Starter
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Re: Broken Input Shaft Symptoms?

Quote:
Originally Posted by HKalin View Post
Let us know what they find.
Roger that.
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post #10 of 19 (permalink) Old Dec 21st, 18, 8:19 AM
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Re: Broken Input Shaft Symptoms?

Quote:
Originally Posted by faded67 View Post
Thanks, yeah that was the thing...no ugly noises. Linkage is all in place, I had a buddy engage it while I looked under and above and it all appears to be working. Its just real soft.
It's real soft because your diaphragm is locked in the disengaged position and you are not getting resistance from it's spring pressure. If you disconnect the return spring, most likely the pedal will drop to the floor.

Your symptoms show that the input shaft is not being driven for one reason or another. Most other reasons would involve obvious noise or grinding/destruction that would have been hard to ignore.
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post #11 of 19 (permalink) Old Dec 28th, 18, 8:30 AM Thread Starter
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Re: Broken Input Shaft Symptoms?

Good Morning everyone. Thank you for all the responses. Due to the holidays, we have not been able to work on the car. I did take a flashlight and look into the housing and can see that the fork is bent. What caused it and whether anything else is broken is yet to be seen. Will need to open everything and do a detailed inspection after the holidays.

Have a safe and Happy New Year to all!

-Rock
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post #12 of 19 (permalink) Old Jan 4th, 19, 8:57 AM Thread Starter
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Re: Broken Input Shaft Symptoms?

Good Morning TC and Happy New Year! Just an update on the tranny issue. So we found that the ring for the bell housing came loose. The ring that came loose is a bell housing adapter someone previously installed to adapt the T10 transmission to the Muncie Bell housing. It's a press fit installation but it came loose somehow and got jammed up in the clutch fork, bearing area preventing the clutch from engaging. As a result, the fork got bent and the bearing damaged and shows evidence of overheating. We drilled three holes in the edge of the ring to "pin" it to the trans housing so it can't come loose again. See pics below. In one of those pictures you can see one or two of the small hole where the pins are installed. Put it all back together and car is running great again!
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post #13 of 19 (permalink) Old Jan 4th, 19, 10:35 AM
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Re: Broken Input Shaft Symptoms?

T10 and Muncie should have the same bearing retainer OD, unless this is a very early T10 (pre-1964). I wonder if that ring is to adapt the T10/Muncie retainer to a truck bellhousing?
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post #14 of 19 (permalink) Old Jan 4th, 19, 10:51 AM
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Re: Broken Input Shaft Symptoms?

Quote:
Originally Posted by faded67 View Post
Good Morning TC and Happy New Year! Just an update on the tranny issue. So we found that the ring for the bell housing came loose. The ring that came loose is a bell housing adapter someone previously installed to adapt the T10 transmission to the Muncie Bell housing. See below! It's a press fit installation but it came loose somehow and got jammed up in the clutch fork, bearing area preventing the clutch from engaging. As a result, the fork got bent and the bearing damaged and shows evidence of overheating. We drilled three holes in the edge of the ring to "pin" it to the trans housing so it can't come loose again. See pics below. In one of those pictures you can see one or two of the small hole where the pins are installed. Put it all back together and car is running great again!


Quote:
Originally Posted by novadude View Post
T10 and Muncie should have the same bearing retainer OD, unless this is a very early T10 (pre-1964). I wonder if that ring is to adapt the T10/Muncie retainer to a truck bellhousing?
^Exactly! Adapts passenger car manual transmissions to a truck bellhousing.

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post #15 of 19 (permalink) Old Jan 4th, 19, 10:54 AM
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Re: Broken Input Shaft Symptoms?

Quote:
Originally Posted by novadude View Post
T10 and Muncie should have the same bearing retainer OD, unless this is a very early T10 (pre-1964). I wonder if that ring is to adapt the T10/Muncie retainer to a truck bellhousing?
I was thinking the same thing when he mentioned the spacer ring. Maybe he'll post a picture of the bellhousing.

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