2 questions about clutch details in '71

[Paul Gordon]

All,

My first question is that I had a new clutch installed in my '71. 1 - 4 is good without any problems. When I try to place it in reverse, I have to grind it in. I was told that Munchie trans will do that until the clutch is worn in. Is that true ?

Next problem, is that now that the clutch is new, I keep blowing a fuse that controls the windows, turn signals, rev lights. Is there a ground wire or hot feed that I could have put back wrong on the starter ?

Thanks Greatly

Paul Gordon Tri-State Pitt's '71

[Joe L.]

Re: 2 questions about clutch details in '71

Paul----

As far as the reverse "grinding" goes, I guess it depends on how much grinding that you experience. Reverse is a non-synchronized, sliding gear. A little grinding when engaging reverse on a Muncie is more-or-less normal. However, if you are experiencing more than a little(as nebulous a term as that is)grinding, I suspect that your clutch adjustment needs to be refined. In the forward, synchronized gears, the synchros could be "overcoming" incomplete disengagement, but in reverse, there's nothing to help out. I've always found that clutch adjustment on a C3 is a real art. There is a very fine line between proper free play and adequate disengagement. Often times, when the clutch is adjusted to provide service manual-specified free play, full clutch disengagement does not occur. Anyway, I've never had a problem with excessive reverse engagement grinding with my '69, including when the car was brand new or after the 3 or so replacements I've installed over the nearly 30 years that I've owned it.

As far as the electrical problem goes, the only ground wire possibility that I can think of is the ground wire which attaches at one of the starter bolts. As I recall, this is a black 14 or 16 gauge wire with a "eyelet" connector. Other than that, there are only 3 electrical connections that you should have disturbed---the "R" and "S" terminals and the main battery cable connection, all located on the starter solenoid. I don't think any of these would cause a problem like you described, but I'd probably check them for tightness and proper installation. Also, if your car is a small block, check to be sure that no part of the lower v-shaped ignition shielding is touching any electrical connections on the solenoid.

[Joe L.]

Re: 2 questions about clutch details in '71

Paul----

As far as the reverse "grinding" goes, I guess it depends on how much grinding that you experience. Reverse is a non-synchronized, sliding gear. A little grinding when engaging reverse on a Muncie is more-or-less normal. However, if you are experiencing more than a little(as nebulous a term as that is)grinding, I suspect that your clutch adjustment needs to be refined. In the forward, synchronized gears, the synchros could be "overcoming" incomplete disengagement, but in reverse, there's nothing to help out. I've always found that clutch adjustment on a C3 is a real art. There is a very fine line between proper free play and adequate disengagement. Often times, when the clutch is adjusted to provide service manual-specified free play, full clutch disengagement does not occur. Anyway, I've never had a problem with excessive reverse engagement grinding with my '69, including when the car was brand new or after the 3 or so replacements I've installed over the nearly 30 years that I've owned it.

As far as the electrical problem goes, the only ground wire possibility that I can think of is the ground wire which attaches at one of the starter bolts. As I recall, this is a black 14 or 16 gauge wire with a "eyelet" connector. Other than that, there are only 3 electrical connections that you should have disturbed---the "R" and "S" terminals and the main battery cable connection, all located on the starter solenoid. I don't think any of these would cause a problem like you described, but I'd probably check them for tightness and proper installation. Also, if your car is a small block, check to be sure that no part of the lower v-shaped ignition shielding is touching any electrical connections on the solenoid.

[Bill W.]

Re: 2 questions about clutch details in '71

Hi Paul,

I can't help with wiring problems, but can offer some advise on the clutch. As Joe said, adjustment is sensitive, you may find as little as one turn on the adjustment nut will give you the "sweet spot" you are looking for. Play with it. Also, if you shift into any other gear just before going into reverse, this will stop the mainshaft/countershaft from roataing, tranny should then slip into reverse easily. Bill

[Bill W.]

Re: 2 questions about clutch details in '71

Hi Paul,

I can't help with wiring problems, but can offer some advise on the clutch. As Joe said, adjustment is sensitive, you may find as little as one turn on the adjustment nut will give you the "sweet spot" you are looking for. Play with it. Also, if you shift into any other gear just before going into reverse, this will stop the mainshaft/countershaft from roataing, tranny should then slip into reverse easily. Bill

[Paul Gordon]

Re: 2 questions about clutch details in '71

Answers:

I found that playing with the adjustment a little more did fix the problem. it was off only a few turns.

As for the wiring. Since the clutch was new, the travel on the linkage is longer. This caused the linkage to pinch the wires. After moving the lines and making sure all was clear. Things were fine.

Thanks for all your help

Paul Gordon Tri-State Pitts

[Paul Gordon]

Re: 2 questions about clutch details in '71

Answers:

I found that playing with the adjustment a little more did fix the problem. it was off only a few turns.

As for the wiring. Since the clutch was new, the travel on the linkage is longer. This caused the linkage to pinch the wires. After moving the lines and making sure all was clear. Things were fine.

Thanks for all your help

Paul Gordon Tri-State Pitts

[Jack H.]

Re: 2 questions about clutch details in '71

(1) As Joe Lucia and the Chevy CSM (Chassis Service Manual) state,

the Muncie 4-speed is NOT synchronized into reverse. When you

intend to shift into reverse, let the RPMs fall, shift into

1st gear that IS synchromesh momentarily, then go into reverse.

Your grinding problems should disappear....

(2) Blowing fuses after you've replaced a clutch (R&R'd the tranny)

on a '71 may well indicate an 'oops' by your shop mechanic. The

tranny linkage includes a multi-circuit electrical switch that

does several jobs including triggering backup lights and the

Corvette 1-year only CEC (combined emissions control) system.

Due to 'design considerations' (a quote from '71 Chevy CSM)

the CEC system includes a reversing relay (as an EE, I read

the statement to be 'oops' in electrical terms) that's mounted

to the driver's side fire wall in conjunction with it's CEC

companion relay (time delay). All this mumbo jumbo says there

are several electrical circuits/functions that monitor or

'watch' the shift lever position of your 4-speed and take

appropriate and distinct actions....

The wires that run to the shift linkage switch and the switch

itself are typically removed during tranny drop. What condition

they were in to start with (after 28 years), what condition

they're in now, how they're routed, what else they might be

touching are issues you should check before looking elsewhere

for the cause of your newly acquired fuse popping symptom.

[Jack H.]

Re: 2 questions about clutch details in '71

(1) As Joe Lucia and the Chevy CSM (Chassis Service Manual) state,

the Muncie 4-speed is NOT synchronized into reverse. When you

intend to shift into reverse, let the RPMs fall, shift into

1st gear that IS synchromesh momentarily, then go into reverse.

Your grinding problems should disappear....

(2) Blowing fuses after you've replaced a clutch (R&R'd the tranny)

on a '71 may well indicate an 'oops' by your shop mechanic. The

tranny linkage includes a multi-circuit electrical switch that

does several jobs including triggering backup lights and the

Corvette 1-year only CEC (combined emissions control) system.

Due to 'design considerations' (a quote from '71 Chevy CSM)

the CEC system includes a reversing relay (as an EE, I read

the statement to be 'oops' in electrical terms) that's mounted

to the driver's side fire wall in conjunction with it's CEC

companion relay (time delay). All this mumbo jumbo says there

are several electrical circuits/functions that monitor or

'watch' the shift lever position of your 4-speed and take

appropriate and distinct actions....

The wires that run to the shift linkage switch and the switch

itself are typically removed during tranny drop. What condition

they were in to start with (after 28 years), what condition

they're in now, how they're routed, what else they might be

touching are issues you should check before looking elsewhere

for the cause of your newly acquired fuse popping symptom.