Transmission Gear Slipping problems of the 2008 Mazda Tribute

Transmission slipping and lurching forward when it engaged at around 20mph with no warning. Checked fluid and almost none left. 14 months old and 48,500 miles. Dealer states that the transmission/ac cooler needs replacement and that it is not part of the 50,000 mile powertrain warranty. $900. Plus to fix. This is a definite safety issue with the lurching and if it is a piece that is needed by the transmission to work properly, it should be covered under the powertrain warranty. Safety bulletin already released on the escapes and hybrids. A recall needs to be done.