Backhoe suddenly stopped going forward, pressure test indicates 0 when shuttle is in forward position
Welcome to HEF Andrew ! Straight 410? 410B,C,D,etc? Serial number?
Straight 410, sn 382549t
Welcome to HEF, Andrew!
Thanks, just looking to exhaust all possible solutions before I split the machine.
mg2361 will guide you through the problem.
Ok
Do you have the tech manual TM1037? What was the pressure in neutral? Reverse? Where did you take that pressure? Is the oil level good? Suction screen clean? New filters? This one is important - Clutch adjustment adjusted properly? Do your hydraulics work? Check the charge pressure to the hydraulic pump and post the results please.
LOL When MG shows up I just watch and learn!
Pressure in revers and nuetral was 135 +, that's on the bottom test port Oil is full and new, new filters. just cleaned the screen, Tested the top test port front zero pressure, didn't get to the rear test yet Did clutch adjust to get the pressure where it was and the free play is close to perfect All hydraulics work although they are a little slow and weak Pressure test on the main pump reads about 2400 at cold start and drops to a little under 2000 when full warm, I think my stroke control adjustment is frozen, cant adjust pressure. Thanks for the help What was the pressure in neutral? Reverse? Where did you take that pressure? Is the oil level good? Suction screen clean? New filters? This one is important - Clutch adjustment adjusted properly? Do your hydraulics work? Check the charge pressure to the hydraulic pump and post the results please.[/QUOTE]
Pressure is a bit low (spec 160). Measured at 2500 rpm? What was the pressure at the other port on the hydraulic pump?
2500 rpm, the test on the charge pressure is 0
It does not move in reverse? It only takes about 90 psi to lock the clutch enough to have some movement. If not....your clutch could be slipping even though it is adjusted correctly. Check both filter reliefs (hyd and trans) for sticking. Inspect the transmission pressure relief for sticking. If all this is OK I would be flow testing the trans pump, but that takes special tooling to accomplish. The only other thing that could be your issue would be a blown gasket on the trans control valve, bad O-rings on the tubes inside the trans case or piston seals on clutches.
Works perfect in reverse. Almost 150 psi in reverse and nuetral, 0 in forward. I replaced both pressure relief valves I also removed the cluth control valve body and replaced everything possible. Is the zero charge pressure because of lack of oil supplied from trans pump? Would it get zero pressure if the main pump screen is plugged and stroke control is stuck?
If reverse is working perfectly and forward is not it is either the steel seal rings on the back of the forward clutch pack or the piston seals on the forward clutch piston. Check the O-rings on the destroke solenoid on the main hydraulic pump. A stuck cooler bypass valve in the clutch control valve could also give you low/no charge pressure. You said you had that out? Yes, stroke control valve could have internal leakage dropping the charge pressure.
Yes, cooler bypass is new and is not stuck, I did find the wires for the destroke solenoid are not connected. The stroke control is stuck, I will need to remove the main pump to get it free. It sounds like it's time to split the machine.
I checked stroke control solenoid, replaced orings cleaned everything and fixed wiring verified it works. Replaced orings on stroke control, cleaned everything, replaced adjustment screw fired it up and still have zero charge pressure
I believe your no forward clutch pressure and charge pressure issues are related. Since it moves fine in reverse that obviously rules out the master clutch and transmission pump. You may have bad forward clutch piston seals. Or the seal rings and bushing behind the forward clutch could be shot as well. The tubes inside for the trans circuit could have a blown O-ring somewhere. Gaskets between the transmission control valve and the trans case could be another possibility which I believe you have already done. I would eliminate all external items first. I think you will be splitting the tractor however.
Thank you, I want to be sure I approach this correctly, I split the tractor at the rear of the engine and then remove the reverser to make these repairs? Is there a list of things I should check or replace since I am taking such a big step?
If you are sure your filter reliefs are good, filters and suction screen are clean and that the transmission control valve spools and springs are all in good shape and you have good trans pressure in neutral and reverse, then I guess splitting the tractor is next. I would be flow testing the transmission pump before splitting but that requires special tooling which you will not be able to acquire. To get to the forward pack you just split the tractor at the engine to clutch housing connection. You will have to remove the clutch shaft to get the forward pack out. If you find nothing wrong with the forward pack then the clutch housing would have to be removed next to access the tube O-rings and that is a much bigger job. If you don't have it you should acquire the tech manual TM1037. From here I guess your on your own. Without being there I have no further ideas as to what may be causing your issue.
Ok. I have about 150 psi in reverse and in nuetral. I will check the clutch adjustment again. I will see if I can check the transmission pump flow. If I lost an inner seal or 0ring, is that usually something instantaneous. I operated the machine one afternoon and everything was fine. Next morning, nothing in forward right from the start.
The clutch will be fine if you have reverse. Is the F/R linkage moving the directional spool far enough?
Im getting a bad feeling about this one.
I disconnected the linkage and moved the f/r lever by hand. It was no different. 0 pressure in forward. When I move it to reverse, pressure goes to 0 for a split send thens climbs quickly.
I would check your control valve gaskets for breaks or missing pieces before I would be pulling the transmission out. One thing I have done frequently is remove the control valve and find the port for the forward clutch on the mounting case. Use a rubber tipped air blower and see if it will hold air pressure. If you hear air rushing inside the transmission then you know its likely blown piston seals, tube line orings, or a split tube line itself.
Clarify control valve . I removed the clutch control valve assembly and replaced all the valves I could and the piston . Everything seemed to be working correctly . I did not test or replace any springs. Another advisor suggested as you did about air pressure into the forward port. I was hoping to do that in the next day or so. Thank you.
This would be my next move.
It's been a while but I'm back. Today attached a hose the the line feeding the main pump. I ran the engine 2500 rpms for 15 seconds got about a gallon in a bucket. Second the I removed the valve body and applied compressed air to the 2 ports to the forward clutch pack and the reverser brake. Front port air just blows through. The rear port I can hear a click and there is back pressure.