I have 2001 Dodge Grand Caravan 3. 3 V6 that will not shift out of low gear. The check engine light comes on. The trouble code is P0607 or P607. I can't remember which. I have been told the problem is the Pressure Control Valve and will cost $900 to replace. I don't know anything about transmissions and wondered what you thought about the diagnosis and the cost to repair.