IH hydrostatic testing

[Roy Suomi]

Do any of you have a IH tech manual that shows hydrostatic transmission testing..A customer of mine referred me to someone that owns an IH loader backhoe with no forward range in it..Things have been slow lately, might take a look at it..Only thing ,I don't want to look like a total rookie..I haven't worked on one of these machines in years..Kinda scarce around here..If you could copy a couple of pages for me , I'd be tickled..Thanks , Roy

 

[Allan in NE]

It won't even attempt to move forward even with the gear selector in "Lo"? Reverse is absolutely fine?

What model is the tractor?

Yeah, I've got all the books, but it is just easier to tell ya how to do it.

Allan

 

[the tractor vet]

It is either built on the 544 or the 656 chassie I have my collection of IT manuals . YA gots a flow rater????? also your going to need a 10,000 lb gauges with steel lines and fittings . myself i have never had the pleasure of working on one so i am not even going to try and kid ya . Now Allen has played with his and lucked out. I am just a bit south of ya.

 

[Roy Suomi]

Yeah...Thats what the man said..hydraulics are good..Reverse is good..No forward...I asked if any hydrostatic whine at all , He said no...I've got excavator guages..Sold my Nuday flo-rater, hadn't used it in years...He did say the trans filter fell apart in his hands..I'm wondering if a piece of filter paper got caught in something in the control circuit...

 

[Allan in NE]

Roy,

I sent you an email. If you'll write me back, I'll send you the pictures of this rascal.

Allan

 

[Owen Aaland]

You can easily determine if the problem is inside the hydro housing or outside with the controls by capping off the the 1/4 inch control lines. You need two 1/4 inch steel JIC flare fitting caps. They need to be steel because of the pressure. Cap the two lines as they come out of the upper left center side of the hydro housing. WARNING!! Once you have these caps on the Foot-N-Inch (clutch) pedal will no longer have any control of the hydro unit. If both forward and reverse now work, the problems is with the external controls. If it still does not work the problem is internal.

If reverse works fine but forward does not, the most likely cause is the forward high pressure relief valve stuck open. The forward valve can be accessed from the left side of the hydro housing. Just below where the two 1/4 inch steel lines enter the hydro housing the is a cover that be removed. You will need to drain at least five gallons of fluid first. Once the cover is removed you can see the two lines on the inside. The short line is connected to the forward relief valve, the longer line goes to the right side and is connected to the reverse relief valve. Remove the short line. You will need to hold the fitting on the valve as you loosen the nut on the line because the torque on the nut is greater than the torque of the installed valve. With the line off, use a small piece of wire through the fitting to measure the distance to the valve piston. Do this carefully so the piston does not move. Remove the valve and make sure the piston moves freely. There is a spring that holds the piston in the closed position but you should be able to move it by hand. With the piston in the closed position, measure the distance again. If it is now longer, you found the problem. The reason for measuring before removing the valve is that often just the act of removing the valve causes it to close.

If you did not find the problem with the relief valve, the next place to look is the shuttle valve. It is located in the same center housing as the relief valves, near the top. It is held in place with a large cap with a slot for a large screwdriver to remove it. Carefully remove the cap and inspect to see if the the snap ring is off end of the shuttle valve. The shuttle valve controls where the charge pump oil flow goes. If thee snap ring comes off the valve will not shift properly to supply make up oil to the hydro unit. Usually this problem causes problems with reverse.

 

[Allan in NE]

Yeah,

With that exploded filter, guess it sure could be an open regulator.

Normally tho, there's a 100 to 1 odds that it is the check valve.

Really doubt if that shuttle valve has anything at all to do with the problem if reverse is "normal as rain".

Allan