Smoking hydrostatic vent

[zoomy]

I was brush mowing yesterday with my L5740 and stopped to pull a branch off the mower deck. I looked up and noticed a small whisp of white smoke coming from the rubber tube that serves as the hydrostatic vent. I pulled out the dipstick and a small amount of white smoke came out also the fluid color looked fine and the smoke seemed to have no smell. Wondering if there is something to be concerned about. Could this be water condensation burning off?

 

[North Idaho Wolfman]

Sounds normal, I'm betting the humidity was up?

 

[zoomy]

Sounds normal, I'm betting the humidity was up?

88 degrees and 80% humidity.

 

[Lil Kubby]

Check he oil temp with a temperature gun if you have or can get one. Sound like hyd. Oil is getting hot. Just to be sure. Hyd oil usually does not discolour if over heated. A little whiff of white vapour is normal but continuos smoke is not

 

[rbargeron]

..... I..noticed a small whisp of white smoke coming from the rubber tube that serves as the hydrostatic vent.......

It's likely water vapor. The gear housings are vented but the hst unit itself is not vented. Its internal charge pump keeps it filled with oil.

A feature of hst drives is they put a lot of shearing energy (heat) into the fluid. The big oil volume in the housings is the heat sink. As temperature rises, heat transfer to the surroundings goes up too, eventually reaching a stable balance. It's not unusual for a running machine to be hot to the touch.

Many machines don't fully heat up every time they run. They can form a small amount of internal condensation. On a full warmup the water vapors off, but it shouldn't last very long.