Pink or milky transmission fluid: water in your transmission

Question from a viewer: I have water in my transmission.

What Chris sees on the bench

• The strawberry milkshake color when the pump and gear come off, which means the transmission had water in it at one time or another.
• Water droplets on the selector valve and pressure regulator assembly. On one 71 series 2.10:1, that was the first sign we found.
• On a bushing-style case, a water mark at the port hole for the rear bushing.
• Rust between the sealing rings on the output shaft and inside the lube cavity of a 1017-004.
• Rust on the selector valve, and inside the forward and reverse apply pistons, where water accumulates.
• A thick goo in the bottom of the sump. That strawberry milkshake makes the pump work harder and the transmission overheat.
• A 5000A that came in with pure water in it, no fluid left at all, plus a 5000V in similar shape.

2001-004 Velvet Drive #5000A

How water gets in

On a ZF63IV that came in with lots of water dripping out of the filter area, Chris's read was that it had either been submerged or had failed coolers. That's why his advice is that if you get water in a transmission, replace the coolers immediately. Salt water is especially rough on the inside of a ZF63IV; a case that came in from salt-water service showed the damage clearly.

Oil coming out of the breather is another tell. The factory lists it as a sign of overheated fluid, the wrong fluid level, or water in the oil, worth tracking down rather than topping off and ignoring.

ZF Marine ZF63IV

On a Liberty, if the fluid shows any water at all, change it before you lay the boat up for winter, not next spring.

Fix and prevention

If you've noticed water in the transmission, take it completely apart. If you do it early, you won't have the rust and you won't have the problems later on. Replace the coolers at the same time. See when to replace your transmission cooler.

When it goes back together, we recommend a Dexron III-type ATF. Don't use synthetic fluid, additives or stop-leak in the old Velvet Drives and Paragons. They swell the O-rings until they break apart. More on which fluid to buy, since Dexron III licenses ended in 2011, in our fluid guide.

When to call

If you drain the fluid and it looks pink, red or milky, call (804) 333-3677, Monday through Friday 9 to 3 Eastern, or email sales@halemarine.com.

Related reading: Velvet Drive transmission fluid, explained and finding and fixing transmission leaks.