my truck has suddenly stoped shifting or advancing into a higher gear it will go on 1991 GMC 1500 Pickup

but stays in the lower gear and reves rpm on the motor.Just moved from the desert in scottsdale az. Any effect from timimg. I am thinking torque converter any suggestions. There ia no leaking of fluid in the transmition

Asked by for the 1991 GMC 1500 Pickup
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