Transmission Gear Slipping problems of the 2009 Dodge Grand Caravan

From the day I purchased this vehicle I have complained to Chrysler multiple times about the transmission slipping. It seems to slip within the first 15 minutes of the caravan being started. It seems to do it when the vehicle has been recently started, when it is shifting between 1st to 2nd gears or 2nd to 3rd gears (not exactly sure what gear it's in when it's making the shift) and it usually always happens when the vehicle is making a turn at a lower speed. The service rep. At the dealership said a lot of vehicles have this transmission and they all seem to have the same issue. He even told me his wife drove a Dodge Grand Caravan and that transmission slipped as well. He also stated that it would be an expensive repair for Chrysler to fix and he stated that if it's not actually broken, then they won't fix it. Recently I was told that my lifetime powertrain warranty had expired because I did not have the transmission inspected within a 90 day period from it's 5 year date of purchase. I was never told that I had to have it inspected, the warranty department at Chrysler said it was in my handbook. . . So I looked it up and it was. I was told it was a lifetime warranty and that's it. They also told me the multiple times I brought the vehicle in for the transmission to be inspected. . . Those inspections did not count as a qualified inspection for the warranty!!! that does not make much sense to me!.