I have a 3.9 in my Dakota, it is basically a 5.2 that has 2 cylinders removed. Maybe the 3.9 and 5.2 water pumps are about the same, I don't know. I replaced my water pump last February. I do know the Dodge dealer wanted I believe somewhere around $265.00 for a new OE water pump. I put a new (not remanned) Duralast pump on my truck, it cost about $58.00 at Autozone with a lifetime warranty. I could not see spending over $250.00 on a water pump for a truck that at the time had 142,000 miles on it. So far I have had absolutely no problems at all from that Duralast pump. The Duralast pump is made right here in the USA, too. BTW, Autozone was also the only place around here that I could find to buy plain old green straight antifreeze. Everyone else sells the "mixes with any type or color" universal coolant. I sure did not want to use that stuff in my truck.