Back flushing/cleaning sump for shuttle/torque con

I bought a Ford 555 loader tractor that won't move because the shuttle won't engage. The previous owner had changed the fluid (very milky looking), and it stopped working, which is why he sold the tractor. I tested the pump pressure and it showed very little pressure with a lot of pulsing on the gauge. I changed the fluid (again, very milky), and got 100 PSI on the test port which is within specification, but the longer the engine ran, the less the pressure became, then started pulsing from 40 - 80 psi. When I would rev up the engine the pressure would drop to almost zero.

When I drained the fluid, it first ran water then milky oil. Also, there was a lot of gray crud while it was draining.

After refilling with fresh fluid, the engine was started and stopped several times. Each time when first starting, the pressure very quickly would jump to 100 PSI, then begin to drop downward to 20 - 40 PSI.

This is seeming to indicate that the sump screen is clogged. No access can be made to it short of breaking apart the tractor and removing the front pump/valve/reversing clutch assembly.

In studying the Ford 555 repair manual, I see that there is a pipe plug in the bottom of the pump assembly that I may be able to get to from the pump test access hole that is covered by the inspection plate at the bottom of the bell housing. If I can remove the pipe plug, it will give me an entry point into the passage between the sump and the pump. I'm considering blowing air and kerosene through it to reverse flush the sump screen, and allow it to drain out the transmission case through the drain plug hole.

Has anyone ever done anything like this on this style Ford? Industrial tractors tend to be parked outside in the weather, and can get water into through the shifter boot. I'm sure this contributes to forming the slimy crud that accumulates on the sump screen.

Also, has anyone tried to add some kind of detergent that will allow the oil and water to mix, then drain it out and refill with fresh fluid?

I just don't want to break the tractor in half to fix the problem.

I had the same concern about the sump screen on my 755 (complete teardown to get at it) and asked a Ford NH mechanic about why they would design a trans with no "easy" way to clean a screen. He said that he has never seen one in all his years that needed to be cleaned, nor has he had to fix one. He said those industrial shuttle trans's were pretty "bullet-proof". (I'm knocking on wood as I type).

Well, I haven't had to flush out a transmission, but other hydraulic systems, yes. I stated to go from the bottom drain for the simple fact that water (and any muck) will sink to the bottom and the drain opening is usually at about the lowest point. The cooler lines would only pick up fluid from a point above the lowest level, as the pick up is usually 1/4 to 1/2" above the bottom. The gap is intentional so the system WON'T pick up and circulate "stuff" that might get in.

You mentioned the cooler lines, the cooler may be clogged if there was a lot of muck circulating. I doubt it is, but taking it off and flushing it out might be a wise precaution. Probably overkill, but...

Yes, after filtering with the 10 micron for a while, cycling thru the gears would probably help. I'm guessing that there might be some fluid trapped that can only get out when the circuit operates. It probably won't be much, but why not? Make sure the wheels are off the ground and the tractor is blocked adequately!

I do have a question, is there a separate hydraulic reservour for the loader and hoe, or is it common with the transmission? If it is common, you will have to flush them out too. One way is to extend all of the cylinders all the way, then undo the line to retract. Work the retract control until the fluid is clear (careful not to run dry!). Then work the control to extend (with it off) and flush that side. Then attach the retract hose and retract the rod. Fluid will gush out. Then attach the extend hose. Yes, it's messy as messy gets, but it's the only way I know of.

Whew, that's a load of work. Hope it gets the machine running again!

jb

It sure sounds like you have a ton of water in the fluid. Here's what I would do, check in the yellow pages for the local hydraulic repair shops. Call them up and ask if thy have a power flush machine for rent to clean out a hydraulic system that is contaminated with water. Our local shop has one for rent at $30 a day + filters. It is an electric pump with dual flters. Buy water trapping filters, probably 3 sets of them in the long size that is about a quart. First set at 50 micron, second set at 10 micron and last set at 2 micron. Have the counter guy sharpie mark them with the size so you do them in order. 50 first, 2 last.

If there is an internal filter in the transmission, change it. If you don't know, go to Ford New Holland and ask the counter guy for a parts breakdown view of the transmission. If there is a filter (99% sure there is), buy a new one. If there is a screen, clean it.

Drain the transmission down and cobble up a fitting from the drain plug to the inlet of the pump. Pour the fluid back into the tractor (why waste it, your gonna filter it right?). Then cobble up a connection from the pump to the trans to return the fluid. It will be pressurized!!

Set the filter system to running, then check the fluid level and add fluid to get it to the top of the range. With the 50 micron filters, run the pump for about an hour to pre-filter out the big chuncks. Then start the tractor up and let it idle while you are filtering (after the 50 micron I would vary rpm level and check pressures). I would go 30 minutes on each filtration level with the tractor running. The fluid should filter out clear. It's up to you if you want to put in new fluid for the final 2 micron filtration.

But, what ever you do, DON'T PUT IN ANY SOAP!

HTH,

jb