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C4 Tranny shift slow from 1st to 2nd...need help

1200 Views 2 Replies 2 Participants Last post by  66conv6
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What could be the causes for a slow shift between 1st and 2nd? 2nd to 3rd shifts fine.

History: The transmission used a lot of transmission fluid one day when my car began to smoke like crazy...I believe that it went into the carb through the modulator valve. I replaced the modulator value, overfilled the transmission and drove ti. Realizing my mistake, I took of the transmission pan to drain off the excess. It's at the right level now, but shift slowly between 1st and 2nd. It also did this when it was overfull. (I had it about a 1 to 1.5 quarts too full).
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I have been told that you can hurt an auto trans by over filling it.
Have you checked for a vacuum leak? The hose that attaches to the modulator often comes loose or is not a good fit. Cheap fix is to cut 1/2" off hose end and reattach or better yet replace the hose. Also check the other end attachment at the carb. There's also a way to adjust the modulator. Do a search here. I've never had to do it. Good luck.
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