Tranny problem - Vintage Mustang Forums
 
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post #1 of 10 (permalink) Old 01-03-2013, 05:55 PM Thread Starter
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Tranny problem

Earlier today I tried to move my car, just across the street, and I discovered a problem with my transmission shifting. I would put the selector into reverse, but the trans would skip down into neutral, then stall. A couple of times it would stay in reverse for a second before shifting back down to neutral, leaving me blocking the middle of my street. After about three or four tries I was able to turn it around and park. I shifted it back and forth a couple times and it didn't do it again. I've been thinking I've had other problems with it shifting drive gears too quickly, (1st-2nd almost as soon as I hit the gas and 2nd-3rd by the time I hit about 15-20 mph) but I was told that's normal for a C4. I'm almost afraid to take it to a transmission shop (if I could even afford it) since I don't want it popping out of drive in the middle of the road. I don't know if these are related but if anyone has any ideas on what may be causing this, any help is appreciated.

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post #2 of 10 (permalink) Old 01-03-2013, 05:59 PM
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I'm assuming the car wasn't warmed up at all during this time, right? Check your transmission fluid level. Might just be slipping because it's low on fluid.

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post #3 of 10 (permalink) Old 01-03-2013, 07:11 PM
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After verifying your fluid level, kickdown linkage and vacuum lines to the modulator and finding no problems I'd head to the local tranny shop.



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post #4 of 10 (permalink) Old 01-05-2013, 08:35 PM Thread Starter
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Checked the fluid level, and it was almost empty, which means it's leaking again since I just changed it about a month ago. I also tried to adjust the modulator and found that it wouldn't adjust, so I'm guessing that's broken. It's also weird that the trans, after being almost empty now says it's over full after adding only one pint of fluid. Doesn't it hold about 7-10 pints?
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post #5 of 10 (permalink) Old 01-05-2013, 09:57 PM
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It's best to check the transmission fluid level when everything is good and hot. Better for it to be a little low than overfilled.

I would recommend replacing the modulator, taking it for a long drive, then checking the fluid level.

If it's leaking, hopefully, it's the rear seal. Those are cheap and easy to fix. If it's the front seal, it's cheap, but it's not easy. You have to drop the transmission.
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post #6 of 10 (permalink) Old 01-05-2013, 10:40 PM
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Quote:
Originally Posted by supercar14 View Post
Checked the fluid level, and it was almost empty, which means it's leaking again since I just changed it about a month ago. I also tried to adjust the modulator and found that it wouldn't adjust, so I'm guessing that's broken. It's also weird that the trans, after being almost empty now says it's over full after adding only one pint of fluid. Doesn't it hold about 7-10 pints?
Sounds like you did have a low fluid problem. Haven't noticed any smoke or anything different coming from the exhaust have you? Maybe the modulator is bad and it's sucking fluid from the modulator into the motor. You would probably have noticed that if it was though.


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post #7 of 10 (permalink) Old 01-06-2013, 09:47 AM Thread Starter
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Originally Posted by horsehead View Post
Sounds like you did have a low fluid problem. Haven't noticed any smoke or anything different coming from the exhaust have you? Maybe the modulator is bad and it's sucking fluid from the modulator into the motor. You would probably have noticed that if it was though.
I do have some engine problems, and I sometimes there is smoke in the exhaust other than when it's warming up. What would be some of the other symptoms if that was happening?
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post #8 of 10 (permalink) Old 01-06-2013, 11:25 AM
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Symptoms of a bad modulator valve are transmission shifting incorrectly, trans fluid level dropping without seeing any leaks. Maybe fouling plugs. I would change the modulator valve. Get the white stripe one.


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post #9 of 10 (permalink) Old 01-06-2013, 12:46 PM Thread Starter
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My modulator is the press-in type. Can you get the white stripe ones in that type, and if so, where?

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post #10 of 10 (permalink) Old 01-06-2013, 06:28 PM
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Should be able to get the white stripe in the press in type. Try your local auto parts supplier. PS---hope it fix's your problem.

Last edited by Horsehead; 01-06-2013 at 06:38 PM.
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