Why doesnt your BMW 1991 525i reverse?

If your 1991 BMW 525i won't reverse, it could be due to several issues, such as low Transmission Fluid, a faulty transmission linkage, or a failing transmission itself. It's also possible that the reverse gear has worn out or the transmission filter is clogged. Checking the transmission fluid level and condition is a good first step, followed by a professional diagnostic if needed.