Truck Repair: TRUCK QUESTION, gmc yukon, transmission overhaul

Question
MY 99 GMC YUKON DRIVES BUT NOT GO IN REVERSE WHAT DOES THAT MEAN

Answer
Hello Sonia,
I would check the transmission fluid level and condition, but it sounds like their is an internal transmission problem.
It would be nice if the control valve was just stuck, but probability of needing a transmission overhaul is high.
Take it to a reputable transmission shop.

Van