4020 loss of transmission pressure

[KSSteve]

I've got an early model 4020D with a powershift. I've owned it about 10 years, and have replaced the hydraulic filters several times, and the fluid at least once. It's always had great transmission pressure, but suddenly it has none.

The shaft to the pump seems to be turning. I replaced the filters, but they looked clean as did the oil in the filter housings. No metal shavings.

I sure don't want to have to pull the pump. Any suggestions would be appreciated.

 

[Mike M]

How's the transmission sump screen ? I saw no mention of it ?

 

[Anonymous-0]

You can't see the shaft for the transmission pump. I don't think the PS uses the front pump.

Check that transmission pump inlet screen and drain the water out of the transmission when it warms up enough to thaw the ice that probably has plugged the suction line.

Gerald J.

 

[DONMYEIL]

Get a set of gauges and test the pressure in the transmission. The trans pump supplies 180 psi to the trans. and then supplies the front pump. That dash gauge is the lube pressure left over after the trans is lubed. It has nothing to do with the front pump.Generaly if there is no lube pressure you have a bad internal leak in the trans. and thats bad $$$$ news.

 

[KSSteve]

How do I check it?

 

[KSSteve]

Thank you for the response. I will check it this next weekend, after I check the inlet screen.

 

[Anonymous-0]

And if you have working hydraulics like steering, three point, and brakes, the transmission pump is working. Could be the gauge is bad.

Gerald J.

 

[Anonymous-0]

I think its at the lower rear corner of the left side of the transmission, behind an internal hex or square pipe plug. You want all the oil out of the transmission first.

Gerald J.

 

[KSSteve]

None of it is working.

 

[KSSteve]

I'll try it this weekend.

I wonder if a dipstick heater would warm the hydraulic fluid up enough to thaw any ice?

 

[TYLERARK]

check the screen first like the others said but If it stopped all at once my money is on the torsional dampner being bad. when they strip out or break, nothing is turning from the flywheel back..
Tyler

 

[KSSteve]

I take it that's really bad news?

I got a service manual on CD today and will start reading the hydraulics section.

 

[TYLERARK]

I wouldnt call it real bad news.
The dampner is basicly a dampened clutch disk which is located in the flywheel. the shaft for the front clutch pack splines into it so it drives the pack, trans pump etc.
I have changed several of these over the years in about all the different Deere powershift tractor models.
Just a simple split between the engine and clutch housing to get to it but get your manual and start from scratch and investigate all possibilities.
I think they are around $560 from Deere and there was a remanned one available from A&I at one time for around $300. I would have to check when I get to work tomorrow to be sure.
Tyler