My mom's 2007 Grand Caravan starts whining very loud after driving 50-100 miles. She has no noise problem with local driving. I talked to one transmission guy who said it was related to the transmission fluid being hot after driving that far, that the transmission was going bad and that mom should sell the car now. But, the van is loaded, so we would like to fix it. Problem is it doesn't make the noise in the shop, so the local dealer fixed a tie rod instead. (Of course, that did not work.) Ideas? Should we flush the transmission?