ZF 280 Transmission oil sample has high sodium

[KnoxWill]

During survey of a freshwater kept 390 one transmission oil sample came back with high sodium. Does anyone have any thought as to why it would have sodium? It is a 2004 and only been in salt water its first 2 years of life. Report mentioned perhaps an additive. What would the additive be?

 

[dtfeld]

Is this the original transmission fluid? Without looking at the report/other levels and it’s only a single report, so no trends. Could be a corrosion inhibitor. Could be some salt water intrusion. It also could be a bad sample or test.

The point of entry would have to be the transmission cooler, which are easy to pressure test and relatively cheap to replace if need be.

If it otherwise runs fine, I wouldn’t worry too much. Have the fluid changed and continue to monitor it. That fluid should be changed at 250hrs or yearly.

 

[KnoxWill]

Is this the original transmission fluid? Without looking at the report/other levels and it’s only a single report, so no trends. Could be a corrosion inhibitor. Could be some salt water intrusion. It also could be a bad sample or test.

The point of entry would have to be the transmission cooler, which are easy to pressure test and relatively cheap to replace if need be.

If it otherwise runs fine, I wouldn’t worry too much. Have the fluid changed and continue to monitor it. That fluid should be changed at 250hrs or yearly.

Thanks for the input. The oil was change about 4 years ago. It is 30W oil. No problems noted when ran last fall. I will keep an eye on it during sea trials next week. I will change immediately after I take possession. Since it is fresh water boat, don't suspect water intrusion. No water noted in lab results. <0.1.