Pics of JD4440 SCV low pressure/motor return port
johndeere1
Posted 8/20/2026 08:22 (#11733018 - in reply to #11732825)
Subject: RE: Pics of JD4440 SCV low pressure/motor return port


Central Saskatchewan Canada
ccjersey - 8/19/2026 22:28

Just so you know the last 3 return options you mention are not all equivalent!

Dumping directly into rear housing is not a great idea as I explained above. It’s for case drains that cannot have any back pressure but results in heat buildup in the oil when used for motor return flow

Agree with everything else. I do like you have been, but made the mistake 20 years ago (following dealer recommendations) of dumping return from a vacuum planter into rear housing through that plug. They had all the fittings in stock! Well, we cooked the front pack in our powershift 4440. Trans housing was so hot water would sizzle on it.

I should have known better since we had been running Vermeer hydraulic drive rakes for years with both hoses plugged into SCV couplers. We also had bought additional supplies to put in return couplers on the old 3020 and 4020 synchro trans tractors that we ran the rakes with for the 20 or 25 years prior to that new recommendation. They got hot too but survived until we wised up and went back to plugging both hoses into SCV couplers.

Swapped planter tractors to finish planting that year and it had no return coupler so we plugged both hoses into SCV and it ran cooler. That’s when I got out tech manual and learned how the system is designed and the implications of dumping return oil to “sump”.


It’s not just cooling the oil that doesn’t happen when you dump return oil to sump. The charge pump supplies the front pump with oil. The charge pump is smaller than the front pump so it depends on return oil from scv to make up the shortfall.
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