When Acura rolled out the 2004 MDX, it wasn’t just another mid-size luxury SUV — it was Honda’s refined answer to families who wanted performance, practicality, and luxury in one sharp-looking package. Under the hood, the MDX came equipped with a 3.5L J35A5 V6 engine paired with a 5-speed automatic transmission (transmission code: B7WA / MJBA / BYBA). Sounds fancy, right? Until, of course, your 2004 Acura MDX transmission decides it’s time to retire.