Ask the Experts

Here’s another Q & A from Jeff Titshall.

Q:  Is a marine transmission directional?

A:  The short answer is YES.

Depending on the make - IE Borg Warner, Paragon, Hurth ZF, PCM - there are some distinct items that need to be in place. Bottom line, there are RH and LH transmissions for RH or LH rotation engines.

The key here is, yes, transmissions are directional, but they can be converted. It will require taking the transmission apart and changing certain parts, but a trained rebuilder is fully capable to do such.

Some are as simple as changing the pump direction (which changes the hydraulic flow internally), while others may require reverse bands to be flipped. With one or two exceptions I can think of, if you try to run a marine transmission in the opposite direction, they will not work.

Marine transmissions are often neglected until they show signs of starting to fail. This is not that much different to how they are treated in automobiles. Bottom line, they are a necessary part of your driveline, and worth the time to check, and service.