3Since you have total loss of hydraulics, after confirming that hydraulic pump shaft is turning, I would remove the hydraulic filter, place a bucket under the filter opening, then start the tractor and see how much oil comes out in 15 seconds. At idle, you should get maybe a gallon. If you get none, then the transmission pump is either failed or the clutch pressure plate has failed and transmission pump is not turning.
JD 2640 Loss of Hydarulics
- Thread starter Rathpr
- Start date
- Views: 31516
-
- Tags
- john deere 2640
Tx Jim
New Member
OK I wasn't thinking about that approach.
I glad you mentioned this. When I removed the cover for the hyd/trans filter, I didn't get it sealed right when bolted back on. When I started tractor hydraulic fluid shoot out cover 6 feet across the room. I would easily say I lost at least a gallon. So hydraulic levels are ok, filters are clean, coupler is connected and spinnin and the pump appears to be working.Im starting to think maybe internal leak, maybe rock shaft seals. Im going to start it up again and remove trans filler cap behind seat and see if there is any spray.
I just thought I would follow through with thread. I ended up taking tractor to JD dealer/service center. The loss of hydraulics was due a small spring breaking apart and was sucked into intake of low pressure pump in the transmission. They had to split the tractor to get to it and make repairs. Also had to replace bearings in high pressure pump in front. Total repair cost was $5,300. Cant believe JD would design something like this where you have to split the tractor to fix a hydraulic pump.
Tx Jim
New Member
Zebrafive
Super Member
Maybe Rathpr will post the bill. I'll guess $1000-1500 for the split. Where the rest went ???? Parts and the front pump repair, maybe another $1000????
The tech notes indicated:
1. checked filter relief valve, surge relief cooler bypass valve, filter, suction screen all good
2. When running head popping noise all hydraulics came back, then lost pressure
3. believe issue is transmission pump or transmission pump drive
4. Replaced hydraulic valves and shifting shaft and resealed with new gaskets and o rings
5. Rolled tractor together and filled with oil, working better but not fast enough
6. Removed hydraulic pump on front and found plastic spacers in crank were gone and plugged pump
7, Rebuilt pump and put together and turned up hydraulic pressure
Labor = $4,655 @ $90/hr
Parts =$ 836
Took about two months to repair
When I got tractor home I have concerns because (1) there is a slight knocking sound not sure if its coming from the engine or the front pump, (2) the service manager told me that the engine needs to be at about 2,000 rpm to have hydraulics working well, (3) the electrical warning light is constantly on. I never had the knocking sound before. I picked up a deck mower yesterday with the three point and did need to have the rpms at about 1,800 to pick it up, never had to do this before and the electrical warning light never turned off. Very very disappointed in JD service
1. checked filter relief valve, surge relief cooler bypass valve, filter, suction screen all good
2. When running head popping noise all hydraulics came back, then lost pressure
3. believe issue is transmission pump or transmission pump drive
4. Replaced hydraulic valves and shifting shaft and resealed with new gaskets and o rings
5. Rolled tractor together and filled with oil, working better but not fast enough
6. Removed hydraulic pump on front and found plastic spacers in crank were gone and plugged pump
7, Rebuilt pump and put together and turned up hydraulic pressure
Labor = $4,655 @ $90/hr
Parts =$ 836
Took about two months to repair
When I got tractor home I have concerns because (1) there is a slight knocking sound not sure if its coming from the engine or the front pump, (2) the service manager told me that the engine needs to be at about 2,000 rpm to have hydraulics working well, (3) the electrical warning light is constantly on. I never had the knocking sound before. I picked up a deck mower yesterday with the three point and did need to have the rpms at about 1,800 to pick it up, never had to do this before and the electrical warning light never turned off. Very very disappointed in JD service
Tx Jim
New Member
Being a former JD dealer service manager at the time 2640's were sold NEW I can't believe a competent/qualified technician can possibly need 51.722222 hrs trying to diagnose & repair the hyd system on a 2640 & then not get it repaired. One should not need 2000 engine rpm's for 2640 hyd's to operate correctly.
The three point should lift a rotary mower at slow idle. If pressure is low at slow idle, there is probably internal leak in rockshaft valves or steering valve. Unless the leak is in transmission pump circuits. When rockshaft lifted, did it lift smoothly or was it jerky? If jerky, most likely pump is cavitating due to not enough oil coming from transmission pump. Actually since you are hearing knocking noise, that could be cavitating sounds also. Sounds like your dealer had someone inexperienced with the older utility tractors working on it. I would go back to them and get them to fix it right. Maybe request that the guy that has been there for thirty or forty years and has experience on those models to work on it. For the amount you were charged every hydraulic component on it should have been replaced or rebuilt and it should work properly...
