A friend of mine has a 1998 328i auto. Friday last week, he was towing a caravan up a steep incline +-5km long in 3rd at 80km/h (3,500RPM). When he started the decent, the car was engulfed in smoke coming from the transmission, or that's what it seemed like 'cause the smoke comes through the gearbox console. This happened again on Sunday when returning home. I drive the same car, manual with a heavier caravan and I had none of the symptoms.
Anyone with experience of this or any ideas as to what the cause might be.
Kind regards MW