Cadillac Repair: 1998 eldo etc, eldo, rpm

Question
QUESTION: when it`s wet out side the trans slips and the RPM go up some times as high as 4000 one day I parked the car  and waited 40 min. and it went back to normal.what do you think

ANSWER: IS or HAS the check engine light ever illuminated when this occurs ?.

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QUESTION: The check engine light did not come

Answer
I honestly have never ran across such a fault and right now am at a loss for any suggestions.

Does the rpm's go high and the trans slip just as you start the car or just as you start to drive it wwithin a mile or does it have to be driven for awhile before this happens ?