C6 disengages after I stop when its cold

C6 disengages after I stop when its cold

Joined: February 20th, 2018, 1:36 am

April 1st, 2018, 5:45 pm #1

Good morning,
When I first start up in the cold morning and put C6 in drive the car will go, but when I stop at the intersection a block away, the car will not go as if the clutch pack has disengaged.
I am planning a rebuild and I am asking about this to learn the possible causes so I fix everything proper.
Would this simply be piston seals? I checked control pressure to be about 55psi in forward and 85psi in reverse at around 1000 rpm.
I currently do not have vacuum gages to make more accurate check.
Please let me know what you know.
Thank you,
Scooter
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Joined: March 23rd, 2004, 11:14 am

April 2nd, 2018, 5:58 am #2

So it comes ok once it is warmed up? What do you then do to get gears again? Could be just old hard seals.
Assuming dipstick "FULL' level is verified correct and it is actually full of oil ?

Pressure seems a bit low if that is at 1000rpm. That pressure is close to specs at idle for a totally stock valvebody. You could simply disconnect the vacuum from the modulator to ensure pressure rises
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Joined: February 20th, 2018, 1:36 am

April 2nd, 2018, 10:39 pm #3

Thank you for the reply.
It does work okay when warmed up. Cold at the times of problem is 10 to 30 degrees F outside here.

When I stop and it wont go again, I move the shifter to park and back to drive and it goes again. It does shift okay. I started letting it warm up more to prevent the stopping.

The dipstick is at "full" checked warm in neutral. The oil is dark and smells bad, so I figure a full rebuild is in order. I have only had it a few months and not sure what problems it had prior.

I will try to get time to check pressure without vacuum connected this weekend.

Thank you.
Scooter
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Joined: March 23rd, 2004, 11:14 am

April 3rd, 2018, 8:25 am #4

Sure sounds like what is referred to as morning sickness. The seals in the clutch drum have gone hard with age and once warmed up they soften and seal.
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Joined: February 20th, 2018, 1:36 am

April 3rd, 2018, 12:29 pm #5

Thank you for the reply.

I bet you are right. I think a thorough rebuild is in order.
Thank you,
Scooter
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Joined: November 18th, 2004, 4:20 am

April 3rd, 2018, 1:46 pm #6

Good morning,
When I first start up in the cold morning and put C6 in drive the car will go, but when I stop at the intersection a block away, the car will not go as if the clutch pack has disengaged.
I am planning a rebuild and I am asking about this to learn the possible causes so I fix everything proper.
Would this simply be piston seals? I checked control pressure to be about 55psi in forward and 85psi in reverse at around 1000 rpm.
I currently do not have vacuum gages to make more accurate check.
Please let me know what you know.
Thank you,
Scooter
Morning sickness is a great possibility but could also be low on fluid.


Mud wasps and critters like to build their nests on breather tubes.

If the breather is clogged it will show a high fluid level even though it shows full.
Crawl under and have a look.
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Scooter
Scooter

April 4th, 2018, 12:27 am #7

Thank you for the reply,
I will be sure to check the breather line. I did not think of that, but we do have mud dobber wasps here.
Thanks,
Scooter
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Joined: November 18th, 2004, 4:20 am

April 7th, 2018, 9:40 pm #8

What did you find?

🤔
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Joined: February 20th, 2018, 1:36 am

April 10th, 2018, 5:56 pm #9

Thank you for checking, but the car is out of town and son has not sent all of my requested pictures.
I did get one picture from him showing it to be push in modulator type, but I still need the whole pan picture.
I will let you know when I can.
Thanks,
Scooter
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Joined: February 20th, 2018, 1:36 am

April 12th, 2018, 3:21 pm #10

What did you find?

🤔
Good morning,
I got pictures of the pan and it does not have chamfered corners in front, so I think based on the push in modulator and pan it should be a late 1973-1975 transmission. That matches the tag that is on the servo cover PGA AU3 AC013692 best I could find to be 1973 mustang.
Thanks,
Scooter
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