Q--My 2006 BMW 330i says that it has “lifetime automatic transmission fluid” that never needs to be changed. I’ve read some discussion by representatives of Redline and Royal Purple (that make synthetic transmission fluid) and they basically say that unless you have a lifetime warranty, it makes sense to change out the transmission fluid at the end of the warranty period. I’m always a big believer in servicing my cars religiously. Who should I trust?
A--Trust your instincts. Unless the automaker is willing to provide a lifetime warranty on the transmission, I would be reluctant to expect the fluid to last the life of the vehicle, which is supposed to be at least 250,000 miles.