JD 2640 Loss of Hydarulics

[Rathpr]

I cannot lift the bucket or three point and the power steering is no longer working. The fluid levels are OK and the hydraulic/transmission filter is clean. Is this an issue with the pump at the front of the tractor? Is there any way to diagnose this? Thanks.

 

[beenthere]

Do you have a pressure gauge to plug in and evaluate your hyd pump pressure?

 

[Rathpr]

Unfortunately I dont

 

[texasranger556]

According to tractordata.com, you have a closed center system. I haven't dealt with closed center systems but a quick Google search of "Deere 2640 hydraulic pump" shows a pump with wires coming off so if everything stopped at once that is where I would start.

 

[Rathpr]

Thanks I take a look

 

[Rara Avis]

Your main hydraulic pump for a JD2640 is located at the front of tractor...I assume you checked your hydraulic level which is found under your right heel...most JD2640's hydraulic dip stick cap was red

Does your 2640 have a pump shut off screw???...many install one to make starting easier

You will need a copy of TM1142 to walk you through all the hydraulic test steps and a Master Hydraulic Fitting Flow Test Kit D-15022NU which can be ordered from JD Service Tools located in Owatonna, MN

Rockshaft Rises Slowly or Fails to Rise
Return valve stuck open
Rockshaft control valve linkage spring failure
Piston o-ring failure
improperly adjusted negative stop screw
improperly adjusted cam follower adjusting screw
improperly adjusted flow control valve
Pressure control valve failure
Transmission pump failure

SCV -cylinder won't extend or moves too slowly
Low transmission oil level
SCV metering valve in low flow position (Adjust)
Load on 3-point hitch less than load on cylinder (Adjust flow control valve)

Loss of steering
Insufficient oil supply to steering valve
--Transmission oil pump not functioning properly or not in operation--(clutch disengaged)
other hydraulic functions receiving priority (Adjust pressure control valve)
Clogged transmission-hydraulic oil filter (Replace filter)
Main hydraulic pump NOT functioning OR pump shut-off screw. IF USED...is in the "off" position (Open pump shut-off screw)
--or repair main hydraulic pump...

 

[DLTTrekkers]

Clean screene and replace hydr filter

 

[DLTTrekkers]

test pressures at right side of gearlevercover to see if gearboxpump is ok.

 

[Spanner]

Clean screene and replace hydr filter

In Post #1 says he checked the filter. Thtat will be the external 'can' filter?

There is an internal screen in the bottom of the transmission case. Access by removing plug cap on RH Side.

A Clogged screen will cause loss of all your functions, especially if steering has gone since steering has priority in the circuit.

You don't say you checked this screen filter. Some models had a steel mesh screen, some had a nylon mesh.

When was the last Trans oil change?

 

[Tx Jim]

Frt hyd pump drive couplers have been known to fail. I would suggest to check coupler to be sure pump shaft is turning when engine crankshaft turns. If tractor is equipped with a manual destroking screw(key 6) I would suggest to turn it down a few turns then turn it out(CW) to it's limit. Only wires on frt pump would lead to an electric operated destroking screw of which I've never seen in person. Is tractor equipped with hyd hi-lo or ind pto? If so do either or both of these hyd functions still operate? Does tractor have a frt end loader?