View Full Version : Tranny Question

01-13-2012, 12:23 PM
Are standard 1:1 trannys rotation specific? Can you swap a counter rotating motor with a standard rotating motor and use the same trans?



01-13-2012, 01:17 PM
transmissions are rotation specific. especially for driving the pump.
I have seen a thread in the past telling how to change the rotation on a transmission if you think you might be up to it. It should not be too hard to search

01-17-2012, 05:45 PM
i think you can use the same tranny just need to adjust the pump see arrow on front of tranny in link but i could be wrong read here i have never tried it or done much reading about it ,i didn't even read the full link that i posted ..


PS maybe you can't ??


01-18-2012, 08:51 AM
It depends on the transmission in question. Borg Warner Velvet Drives can be used in either direction (by indexing the pump), but can NOT reverse the direction of rotation of the engine. LH engines can only spin LH props, RH engines can only spin RH props.

Other types of trannies (ZF Hurth, etc) CAN reverse the direction of prop rotation... meaning you can use a LH engine to turn a RH prop OR a LH prop (and vice versa).

Others can ONLY reverse the direction of engine rotation... like the PCM 1.23:1 Powerplus.

So... it depends what transmission youre talking about.

01-18-2012, 08:58 AM
Friend of mine bought a 82' correct craft last year with a dead 350, he pulled a nice 350 out of a 72' sleekcraft that I sold him (it was a crate motor with very few hours on it) after installing the motor he put the boat in the water fired it up, put it in reverse and it tried to climb the trailer. He called a local guy that is very knowlageable with direct drive trannys and was told to chage the direction of the arrows on the pump (very easy to do) and put the motor back in. Works perfectly!!!!

(forgot to mention that the prop also needed to be changed for direction)