John Deere 2940 No oil to front pump

wogdalton · Dec 12, 2013

The hitch and steering started going away and got worst as the day went on. Now none of the hydraulics work. I have changed the filter and oil and have cleaned the screen. I cant seem to get any supply oil to the front pump. Any help?

buickanddeere · Dec 12, 2013

Pto and high/low shift still work?
Access to pressure gauges ?

wogdalton · Dec 12, 2013

I didnt think to check the pto. I do have pressure gauges but i have already removed the front pump. I just thought it was weird that there was no oil coming out of the supply line to the pump and the little tank above the pump was empty. I dont think there was ever any oil getting to the pump and I dont want to install the new pump until im sure that its getting oil. Maybe the old pump is still good.

buickanddeere · Dec 13, 2013

wogdalton said:
I didnt think to check the pto. I do have pressure gauges but i have already removed the front pump. I just thought it was weird that there was no oil coming out of the supply line to the pump and the little tank above the pump was empty. I dont think there was ever any oil getting to the pump and I dont want to install the new pump until im sure that its getting oil. Maybe the old pump is still good.

It's unusual that lack of oil supply to the front pump is noticed until one or two new front pumps are installed. I would estimate there are 100 front pump jobs performed for every 2 actual pump failures.
There is usually a broken transmission internal line or fitting. Or a stuck valve in the transmission low pressure hydraulic circuit. A failed high/low clutch pack, failed pto clutch or failed pto brake will also bleed oil. On occasion the problem is as simple as an trans oil filter o'ring stuck in a valve.
The parts list on the JD web site shows the locations of the transmission's divert and relief valves. If the trans filter has ever been plugged . The internal transmission oil lines can shake and break due to valves hammering.

Tx Jim · Dec 13, 2013

Ditto b&d those closed center frt pumps are very durable and as stated are often unnecessarily replaced

Zebrafive · Dec 13, 2013

I am with buickanddeere.

Check the trans filter relief valve (maybe Tx Jim can find and post a picture of the parts drawing).

Next see if PTO engaged/disengaged makes a difference. The PTO clutch line broke in my 2030 and I lost hydraulics when engaged and they worked when disengaged. It to took splitting the tractor to replace the line. it was broke in two I replaced only the PTO clutch line. I wish I had also replaced the PTO brake line.

Check with trans in HI and LO.

The other possibility not covered is broken pump lines (internal) suction or pressure from the trans pump.