93 rodeo tranny problem

when driving the check tranny light comes on, goes into limp mode. when i turn off the key and restart its fine then keeps doing it again. if checked things from other posts but cant seem to figure it out. i have checked the voltage it is between 14.24 and goes to 15.01 when i accelerate the throttle doesnt this seem like the correct voltage. any help anyone could offer would be greatly appreciated thanks mike

Have you checked the transmission fluid level/color?