Changing Pump Rotation on a Velvet Drive
Step by step
- Loosen and remove the bolts around the pump.
- Tap the pump loose. There's a little appendage on the pump that's a good spot to hit. On an old transmission you might have to hit it several times.
- Rotate the pump 180 degrees, so the rotation arrow points to the opposite side from where it started.
- Reinsert the bolts. The transmission is now set for the opposite hand rotation.
What pump rotation actually changes
This is the part that trips people up: changing pump rotation only changes which side of the pump the fluid gets pumped to, matching the direction your flywheel turns. It does not change which shift-lever position (forward or reverse) drives the boat forward, and it does not change the output shaft's rotation direction. Before doing anything else on a cast-iron unit, bump the starter and watch the flywheel direction, then check the arrow on the pump. If they don't match, the transmission's not going to move.
Why the pump direction matters at all
The pump has a crescent-shaped piece inside it. As it turns, fluid comes around the crescent, gets forced out of the gears, and pushes into the forward/reverse adapter and on through the passage to the selector valve and the rest of the transmission. That's why the arrow on the pump needs to go the same direction as the flywheel. It has nothing to do with which shift position the boat moves forward in.
Why getting this wrong is expensive
The shift lever has to be in the forward position to go forward. If you run it in the reverse position to make the boat go forward, you'll cook your transmission. We've torn down a 1017-004 that had been run this way: it melted and destroyed the gears in the planetary, and ate the drum. Flipping pump rotation won't change which lever position is forward, so if yours feels backwards, give us a call before you run it.
Paragon transmissions: different procedure
Paragon transmissions use a different plate to access rotation. Take the two recessed bolts holding the plate off, one on top and one on the bottom. Do not touch the bolts that hold the pump on. When you lift the plate off, hold the input shaft down at the same time. Pulling the plate up on its own can drag the input shaft with it and break the sealing rings. For Ford applications, Chris doesn't remember Paragon ever making one that ran opposite of automotive rotation.
ZF and 5000-series note
ZF transmissions and the 5000-series Velvet Drives work differently. Chris says they only work for left-hand engines and they're bidirectional, meaning they have the same capacity in forward and reverse.
Questions about your setup before you start? Call (804) 333-3677, Monday through Friday 9 to 3 Eastern, or email sales@halemarine.com.
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Common questions
Does changing pump rotation change which way my propeller shaft turns?
No. It only changes which side of the pump the fluid is directed to, matching the engine's flywheel rotation. It does not change the output shaft direction or which shift lever position drives the boat forward.
How do I change rotation on a Paragon transmission?
Remove the two recessed bolts holding the rotation plate (not the pump-retaining bolts), and hold the input shaft down while lifting the plate to avoid breaking the sealing rings.