Jim Steinman, who wrote and produced huge hits for Meat Loaf, Air Supply, Celine Dion and Bonnie Tyler, is dead … TMZ has learned.

Steinman died Monday in Connecticut, according to the state’s medical examiner. The cause of death is unclear. We do know it appears it was sudden … there was a medical emergency call to his home around 3:30 AM Sunday to transport a male patient.

Jim’s perhaps best known for his songwriting work on Meat Loaf’s “Bat Out of Hell” — one of the best selling albums of all time — and “Bat…