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Late 70’s to early 80’s JD 570A needs help

Phil P

Well-Known Member
Joined
May 13, 2016
Messages
166
Location
Florida
Occupation
Consultant
Hello all

Here I am ageing with an old piece of equipment.

This unit doesn’t have a data tag on it so I guess the year to be some time around late 70’s to early 80’s

So here is the story.

Engine removed and overhauled 10 years ago. In stead of repairing the brakes the brake system was caped to N.S. condition. The rticulated frame has been blocked in the straight position and the hydraulic system for that was caped and is no longer serviceable. The moldboard has severe wear on it (most fasteners are in half holes) from being used with a totally worn out cutting edge.

So to say the least this unit is a refuge from the scrap yard.

I had replace cutting edge and done several other things to keep it operating.

The unit was parked about 3 months ago and was working fairly well at that time.

All fluids were checked and it was started a couple of days ago to do some work on the shell road that is the main entranceto this ranch. The engine started and ran good but there was no indication of hydraulic or transmission oil pressure.

There’s a rattling noise that was not present before in the rear of the engine.

I have checked all the controls that are provided to disconnect the transmission for towing and the engine from the driveline. They are in the proper position.

I have tried to give you all the information I can think of to see if there is any recommendation on finding a solution to the problem.

The problem is hydraulics and driveline has no power to them.

Phil P
 

Diesel Dave

Senior Member
Joined
Sep 29, 2022
Messages
1,041
Location
Ontario Canada
I suspect the splines on the engine clutch disk or splines on the transmission input shaft have failed.
The transmission pump is driven directly by the input shaft and supplies oil to the hydraulic pump at the radiator support and of course the transmission control valves.
 

Delmer

Senior Member
Joined
Jan 3, 2013
Messages
8,863
Location
WI
Does this have a "engine start transmission disconnect", also known as a dry clutch but not the left pedal, some oddball location that got moved but not noticed?
 

Phil P

Well-Known Member
Joined
May 13, 2016
Messages
166
Location
Florida
Occupation
Consultant
Thanks to both of you.

Delmer

You are correct there is a dry clutch that is the engine disconnect clutch that is recommended to be disengaged for the start. This has never worked sense I have known this motor grader. The engine was removed and rebuilt then reinstalled without removing the transfer case and I suspect the linkage was never properly reinstalled. This work was performed about 3 months before I came in contact with any of this equipment 10 years ago.

Diesel Dave

I have the same manual that picture came out of. The schematic of the oil system shows that low pressure line from the transmission pump to the hydraulic pump. My concern is determining if it is the clutch,transfer gear box or the transmission. There is no access to the clutch without removing the transfer gear box. If either one of you have had one of these apart can you tell me if I can see enough thru the plug marked by the manual as a “oil fill” plug to tell if the gear train is moving? I know the unit is lubricated by hydraulic supplied thru that tube that goes to the top of the gear box on the passenger side of the unit. The only reason I can see for a oil fill plug is to oil the unit before the first start after repair.

I have removed the fuel tank but can still run the engine using a rubber hose pickup and a 5 gallon jug of fuel. Weather permitting I will do this tomorrow.

The noise we are hearing we thought was coming from the transfer gear box and I didn’t have time to run it after removing the fuel tank. I just wonder if I remove that plug if I could see the gear train is moving or not thru the hole.

Just to let you all know I have only myself and one helper and we are both part time in the maintenance department. My helper also takes care of the irrigation system that is quite extensive.

This ranch is 16 square miles in sizes and then there is an extension about half that sizes located about 30 miles away. Please don’t get the idea I am not paying attrition to this forum it just sometimes it's a few days or so before I can get on the computer.

Phil P
 

Phil P

Well-Known Member
Joined
May 13, 2016
Messages
166
Location
Florida
Occupation
Consultant
Hi

Thanks for your help.

Removed the hub cap on the upper shaft of the transfer case and found it doesn’t turn when engine is running.

We are in the process of removing the transfer case.
 

Phil P

Well-Known Member
Joined
May 13, 2016
Messages
166
Location
Florida
Occupation
Consultant
Hi

The transfer case has been removed.

The spline shaft from the clutch plate to the transfer case is stripped at the case end. The gear doesn’t look good either.

I have now remove the upper gear and found it to be striped as well.

No parts available new or used.

A local machinist is going to machine the gear to a press fit with the spline shaft this will require welding and machining. The final product will be the gear permanently affixed to the spline shaft.

I will let you all know if this works out.

Phil P
 

Phil P

Well-Known Member
Joined
May 13, 2016
Messages
166
Location
Florida
Occupation
Consultant
Hello all

We have established the year of manufacturer as 1969 by the markings on the inside of the transfer gearbox.

My local machinist didn’t like the press fit and welding thing so he repaired both the gear and the shaft to a proper spline fit.

Here are pictures remember the shaft and gear were striped all most smooth. Unfortunately I didn’t make pictures of them before repair.

Here are pictures of the repaired parts.

Phil P

PS I put bearings on after repair.
 

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Phil P

Well-Known Member
Joined
May 13, 2016
Messages
166
Location
Florida
Occupation
Consultant
Hi

We finished the machine yesterday 6/16/2023 and put it in service. It was to be used in the afternoon and I haven’t heard anything so I assume it is operating correctly.

Phil P
 
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