I have a 53 reg Merc S320 CDI, which has covered 120,000 miles. Last year (20,000 miles ago) I had to have the transmission rebuilt (ingress of water glycol). This cost £3000+ (thankfully, £1000 paid by A1 Warranties) and was carried out by an auto specialist. The new cooling radiator failed almost immediately and the whole job was repeated, at no cost to me. Recently, the box has been behaving oddly, sometimes moving into top gear very soon after starting off, refusing to kick down or refusing to change down other than by manually using the +/- lever change. After a few instances of manual changing, the box rights itself, but nevertheless I am thinking of a change. I have heard that most makes have suffered. Has the water glycol problem been overcome on newer cars or is it better to steer clear of autos until it has. Also, should a 2003 S320 CDI be run on the new super diesel or is the engine too old. Are the two subjects connected?