New to us 720 A

[3D1]

We have been trying to work the bugs out of our new 720 A . It has had transmission issues since we got it. Reverse always works but sometimes it looses all forward gears.

I have been going through the electrical system. Cleaning plugs , dielectric grease ect. Changed the alternator today and got the volts up to 14.4 on the batteries when running. I have already changed all of the filters and drained and filled the trans .

I need to build a pressure gage set up. I saw that a Transmission pressure gage was an option from the factory. I would like to get a long hose so I could match the pressure from the cab.

Any idea why it the problem would come and go ? I ran it the other day for a few hours. It never slipped in any gear under heavy load. And now it won't go forward again.

I know I saw a service manual for checking pressures and diagnosis. But I can't seem to find it now.

 

[Silveroddo]

Does it flash any codes in the selector screen when it acts up?

 

[James Sorochan]

3D1. You can find some manuals and parts books on the Sierra Park Champion grader site. You might want to check the forward Reverse micro switch to see if it's working properly. You have to make sure all your grounds are good and clean and battery is giving your full 12 volts otherwise this sort of problem can happen.

 

[3D1]

It flashes CH , and then 2.7 . Do you have to disassemble the shifter to access the microswitch?

 

[James Sorochan]

Does yours look the same as 710A? Here is a pic of mine. I undid the bolts and lifted the console up. The micro switch was on the bottom of the F/R lever.

 

[3D1]

Thanks , I found the manuals on Sierra park. I couldn't remember where those were. That is the same shifter . I will remove it next.

 

[3D1]

Ok , so I pulled the shifter and checked the voltage on the micro switch . Not sure if I was checking it correctly but it seemed to change with the gears on my volt meter.

When I had the shifter removed I pulled all 6 plugs from the bottom of the console area and all of the grounds for the relays. Cleaned the grounds and the post . Used dialectic grease going back together with everything.

I also pulled apart all of the plugs in the articulation area . Cleaned them and used grease going back together.

Still flashing 2.7 when I turn on the key. One thing I did notice is the volt meter is higher than it was. I think I am making progress. Still searching for the problem.

 

[Welder Dave]

One of the manuals tells what the codes mean. I think 2.7 means no power or bad grounds but I'm not sure.

 

[3D1]

Thank you , to everyone who adds to this forum. We go our blade working again but it went a different direction than I thought. I learned alot , once a real mechanic showed up it was easy.

My controller was telling the solenoids what to do , but they were not responding. We pulled the stem and it was covered in metal .

Who ever ran this machine in the past didn't care about it. My mechanic tells me once you run a GP Deere it is hard to use a clutch. Clutch drops was his hypothesis. Lots of filter changes and new oil in our future. And now I have the tools to pull the stem and clean the screens if I get stranded.

 

[3D1]

So this is what we have been fighting. The screen on the stem fills with clutch parts , and we have no forward gears. I am really good at pulling the coil and stem at this point.