#2266: The Double Groan : The Best of Car Talk Janice from Pasadena has a Mercedes that can't climb hills. She has taken it to several mechanics who are trying to help but can't figure it out. It could be the transmission or it could be the engine. Will Click and Clack take opposing sides on this diagnosis or is Janice going to get the dreaded 'double groan'? Find out on this episode of the Best of Car Talk.