Probably a loose bearing?

I have no knowledge of cars other than how to drive them and fill them with kids and run errands. We have a 2003 Honda Odyssey Minivan with 145,000 miles. Prepping for a 2,500 mile road trip, I took it to my mechanic for a look over and asked them to look into a sound that is linked to acceleration. It sound when i push the gas, and lets upnwhen i Take my foot off. It’s a sort of whine but gets higher pitched as the day goes on. They say that it is probably a loose bearing in the transmission and my choices are wait and see or re-build the transmission. Wait and see might work if I didn’t have two kids in the car-I am concerned about highway safety. So…am I overly cautious? Or do I re-build or…buy a new (used) car.? Is rebuilding a transmission like getting a new car minus the smell?

Ordering expensive repairs based on guesswork is no guarantee the problem will be solved…At 145K miles your Honda is getting ready to present you with a LOT of expensive repairs and its reliability on 2500 mile trips is not what it once was…Another used car will offer little or no improvement. Rebuilding your transmission ($$$$$) is NOT like getting a new car. It’s the same old car with a new transmission…