C4 problem

After making a pass at the drag strip last weekend my C4 lost the forward gears. It still had reverse and after it cooled down the forward gears worked again. It is an old C4 with a manual valve body and a 2500 stall.
I raced the car later in the day grude matching against some friends, on the 3rd passes the tranny lost the forward gears on line. I had the car towwed home and when I got home the tranny worked again.
I have the tranny out of the car and plan to put another in so I can drive the car but want to fix the old tranny. What do think is broken.
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Forward clutches are overheated. Needs a complete overhaul.
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Thats what I assumed but have never thaken a C4 apart.
Thanks Roger
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Did you have a tranny cooler with that converter?

Yes, I installed a tranny cooler and also a big electric fan. Tha motor temp never got above 180.
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Same here. My engine temps have never gotten higher than 180 with the alcohol, more commonly it never goes above 140. 180 when hot lapping in the final rounds.

Trans temps have been over 200, however, on numerous occasions. Switching to Synthetic ATF dropped those trans temps 15-20 degrees and it is a little more consistent in the 60'. Most of the time trans temps are in the neighborhood of 140-160. 180 is the hottest I've seen it since changing to syn. fluid and that was on Ford day. I ran 3 classes that day...22 passes total and the last 6 were within 20-30 minutes of each other.
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