Have the codes read. Go to a Auto Zone done for free. It sounds like the Vehicle input speed sensor is bad. The code would confirm. What you describe sounds like the problem. The part is also called a turbine speed sensor. On the jeep it is located on the drivers side of the transmission toward the front should be white in color with a 4 wire plug it just unscrews and screw the new one in. They are not that expensive.
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