John Deere 2040 No Hydraulic Oil Getting to Filter

[LDCravey]

My brother asked me to look at his JD 2040 (SN 407877) (no independent hydraulics, closed center hydraulics) because it lost power steering and the lift arms will not raise. He said he pulled the hydraulic oil filter and it was collapsed, so he replaced the hydraulic filter, then replaced all the hydraulic fluid. I told him to clean the hydraulic screen and the filter bypass valve also. So, he drained the hydraulic oil again, and checked the screen and bypass filter. The screen was clogged and the filter bypass valve was frozen. The screen is now clean and the bypass valve is moving freely.

I put his tractor on my trailer and brought it to my large garage so that I could easily work on it in the comfort of a heated garage. I drained the hydraulic oil (again) and checked the screen and bypass valve. Both were clean and working. I pulled the hydraulic filter housing and noticed that it looked like there was no hydraulic oil going into the filter since my brother had installed another filter. Using a bright light, I noticed some hydraulic gunk in the bottom of the transmission case, so I got a long wire with a paper towel wrapped tightly to the end of the wire and swabbed out the bottom of the transmission case. There was some gunk, but it really was not bad.

Using a large rubber stopper with a 1/4" nylon hose inserted into the rubber stopper, I then blew high pressure air up into the side hydraulic drain plug port (where the screen is located). I could feel air coming from the port hole of the hydraulic filter. I then blew air backwards from the port hole of the hydraulic filter into the (rear) hydraulic pump outlet and could feel air coming out the hydraulic drain port. I also blew air into the hydraulic fill port (in the rear of the rock shaft cover) and could feel air coming out of both the drain port and out of the (rear) hydraulic pump outlet. (The hydraulic pump "outlet" is built into the transmission case right at the hydraulic filter.) (See pictures). I used a very fine paint filter to refill the (essentially new) hydraulic oil and then cranked the tractor. Still no hydraulic oil flowing to the hydraulic filter.

I then pulled the rock shaft cover to see if there was anything obvious in the transmission case before I split the tractor to check the rear hydraulic pump.

I found that one oil line (#6) appears to have a crack in it (see close up picture) however, this oil line is not pressurized and (apparently) only gets hydraulic fluid dripped into it from the "collar shift" oil cup (#1). I filled this oil cup and did not see any fluid dripping from the cracked line. I'll braze this line, but only after determining why the hydraulic filter is not filling up.

One more thing unusual, the hydraulic oil dip stick indicates full, however, when I drained it, there was only about 4..1 gallons. The manual says 7.4 gallons. (This tractor does not have external hydraulics or a FEL.)

Anyone got any suggestions as to why the hydraulic oil filter is not getting oil. I am not someone who randomly replaces the rear hydraulic pump unless I can prove that it is bad. It is clearly not sucking oil into the input of the rear pump. Next step if slit the tractor and check the rear hydraulic pump.

 

[Tx Jim]

I have read that there is a transmission pump line on RH side of trans case that can cause hyd problems on JD utility tractors with closed-center hyd systems. I searched internet unsuccessfully for that faulty trans pump line information. IIRC there is a JD service bulletin that refers to that faulty line. I agree that dry transmissions normally hold more hyd oil than amount required during oil change but 7.4 gallons to 4.1 gallons sounds excessive. Have you checked surge relief valve to be sure it's seating? Did you check that no foreign debris was inside filter relief valve(T22853)?? I thought trans pump could be R&R without need to split tractor.

 

[Jim.ME]

I think there are two drain plugs. Did you pull both drain plugs in the transmission/differential case and drain both sections? If it has two and you only pulled one, that could explain why it didn't take as much oil to refill it.

 

[Tx Jim]

I think there are two drain plugs. Did you pull both drain plugs in the transmission/differential case and drain both sections? If it has two and you only pulled one, that could explain why it didn't take as much oil to refill it.

Only one trans case drain plug is shown in 2040 parts catalog

 

[LDCravey]

I have read that there is a transmission pump line on RH side of trans case that can cause hyd problems on JD utility tractors with closed-center hyd systems. I searched internet unsuccessfully for that faulty trans pump line information. IIRC there is a JD service bulletin that refers to that faulty line. I agree that dry transmissions normally hold more hyd oil than amount required during oil change but 7.4 gallons to 4.1 gallons sounds excessive. Have you checked surge relief valve to be sure it's seating? Did you check that no foreign debris was inside filter relief valve(T22853)?? I thought trans pump could be R&R without need to split tractor.

The filter bypass valve and the filter relief valve are the same thing. It is definitely moving freely because I checked it 3 times. The output of the pump comes out of the sidewall of the transmission housing directly into the filter canister as shown in the first two pictures. (This is somewhat hard to describe without actually seeing it and tracing the route of the line.) I even removed this bypass (aka "relief") valve, along with the filter removed, while it was full of transmission oil and cranked tractor at same time, still no oil flow to filter. I ran a #14awg stranded copper wire up, from filter input, into the output of the hydraulic pump and was able to get about 6" of wire inside. It came out perfectly clean with no gunk.

I am beginning to suspect that the input (suction) pipe to the rear hydraulic pump is broken or disconnected or cracked. The hydraulic screen (apparently) is directly connected (at the transmission case) to that pipe, which feeds the hydraulic pump.

 

[LDCravey]

I think there are two drain plugs. Did you pull both drain plugs in the transmission/differential case and drain both sections? If it has two and you only pulled one, that could explain why it didn't take as much oil to refill it.

You are probably correct that there are 2 drain plugs. I will confirm later today. While I have the rockshaft cover removed (waiting on a RS gasket), I measured 5" (depth) of hydraulic oil in the rear section of the transmission case and only 2" (depth) in the front section of the transmission case

 

[Jim.ME]

Only one trans case drain plug is shown in 2040 parts catalog

I agree with you on what the parts manual shows, however an operator's manual for 350000> shows two. It appears a visual check to see what there is, is required.

 

[Jim.ME]

You are probably correct that there are 2 drain plugs. I will confirm later today. While I have the rockshaft cover removed (waiting on a RS gasket), I measured 5" (depth) of hydraulic oil in the rear section of the transmission case and only 2" (depth) in the front section of the transmission case

Do you have the Operator's Manual for your tractor?

 

[Tx Jim]

I agree with you on what the parts manual shows, however an operator's manual for 350000> shows two. It appears a visual check to see what there is, is required.

Did you view operators manual for 2040 that stated built in US WBTW is incorrect as all 2040's were built in Mannheim? Parts catalog for 2040 built for sales in European countries shows 2 trans case drain plugs.

 

[LDCravey]

Yes, I have operators manual (116 pages), parts manual (581 pages) and JD service (technical) manuals (586 pages)`. I even have the service manual in French! And.... I don't even speak French.

 

[LDCravey]

Did you view operators manual for 2040 that stated built in US WBTW is incorrect as all 2040's were built in Mannheim? Parts catalog for 2040 built for sales in European countries shows 2 trans case drain plugs.

Once the furnace warms up the 2400sq ft garage to a nice balmy 70°, I will check to see if there are 2 drain plugs. I still have the rockshaft cover off (awaiting RS gasket), so I might drain oil again to see if both sections of the transmission case drain. This 2040 was definitely made in Mannheim.

 

[Tx Jim]

Did you also order/get quad ring part # T17882 that fits between trans case & rockshaft housing?

 

[LDCravey]

Did you also order/get quad ring part # T17882 that fits between trans case & rockshaft housing?

No, I did not order that quad ring since it does not appear to be used on this particular 2040 at the point show. There is no place for it. I only found 1 (pressurized?) oil connection from transmission case to rockshaft housing (see picture) and it does not show any o-ring. All other holes in the RS gasket are used for bolt holes (2 holes are for RS locating pins). Perhaps JD made a mistake in the parts manual and should have shown that quad ring at the arrows in my picture, since it is the only pressurized oil connection to the rockshaft housing? The JD engineers certainly didn't get any awards for their parts descriptions!

 

[Tx Jim]

I'll guarantee you that your tractor utilizes a T17882 quad ring. JD utility tractors used T17882 from 1965-1992

 

[LDCravey]

I agree with you on what the parts manual shows, however an operator's manual for 350000> shows two. It appears a visual check to see what there is, is required.

You are correct Jim.ME. There are two hydraulic drain plugs. I just picked up the transmission case to clutch housing gasket. I am splitting the tractor tomorrow to see what is happening with the suction from the rear pump.

 

[Jim.ME]

Did you view operators manual for 2040 that stated built in US WBTW is incorrect as all 2040's were built in Mannheim? Parts catalog for 2040 built for sales in European countries shows 2 trans case drain plugs.

I looked at the Op manual for s/n 350000 and up (OMR718590), same as the one he posted after I made my post. Picture on page 83 shows two plugs to drain. It appears he has located the second plug.

 

[Jim.ME]

You are correct Jim.ME. There are two hydraulic drain plugs. I just picked up the transmission case to clutch housing gasket. I am splitting the tractor tomorrow to see what is happening with the suction from the rear pump.

Good, draining the rear compartment will increase the oil you need to fill it. It is not uncommon that not everything will drain out even with both plugs out. Also do you follow the procedure to check the level engine at low idle found on page 76 of your Operator's Manual. There is often a difference in level if checked with the engine shut off.

 

[LDCravey]

I'll guarantee you that your tractor utilizes a T17882 quad ring. JD utility tractors used T17882 from 1965-1992

You are correct TX Jim. There is a quad ring but it is not located at the correct location in the first picture you sent, however, the in the last (combined) pictures, it is correctly located in the middle and lower picture. The upper picture apparently shows it in the wrong location. Thanks for the "heads up", since the old quad ring was so flat in the transmission case, that if felt like a gasket stuck to the transmission case. I knew that it had to have some kind of seal at this location since lower pressure fluid comes up into the rockshaft cylinder at this point and I knew that the rockshaft gasket could not possibly seal even low pressure hydraulic fluid.

I picked up that quad washer today along with the rockshaft cover gasket and transmission housing to clutch housing gasket. I am going reassemble the rockshaft cover and seat, move the tractor to another garage bay, then split the tractor tomorrow to hopefully determine why the rear hydraulic pump is not sucking any oil.

I'll let everyone know what the real reason is that no oil is flowing into the filter soon. I also need to braze up that cracked oil line from the oil cup that I found earlier.