JD 310SJ no fwd or reverse

[vikingsven]

Hi guys
I have another issue with my backhoe and need help diagnosing. I recently installed new batteries and the engine runs fine. No error codes, everything seems to function properly except it won't go into any gear. I did this once before but started working randomly. I thought it was from a loose brake pressure sensor wire. After parking it and letting it sit for a while, it is once again not moving. Transmission oil level is good. All trans diagnostics pass. FNR and all gears are displayed on the monitor properly.

Thoughts?

 

[vikingsven]

Forgot to add, the parking brake does not seem to be engaged, regardless of the parking brake switch position. I can lift the rear with the stabs and the rear tires can be moved by hand regardless of switch position. Parking brake override bolts are backed out ~1".

Also, all fuses look good

 

[ohdeereme]

Raise one rear wheel and see if it can be turned. With both wheels raised they will turn opposite each other because of the spider gears. Is the park brake light going off ? If this is a 4WD machine see if ithe front wheels will pull with 4WD turned on or see if it will pull with the rear differential lock engaged. Try that and update with the SN.

 

[vikingsven]

Hi Ohdeereme,
When I ran some tests over the weekend I did just as you described. Rear wheels turned with and without the park brake engaged. Not sure why since it's supposed to be spring applied when off? When the button is pressed to disengage the light goes out as expected, but I couldn't feel the solenoid engage. In 4wd there was no difference. Diff lock engaged didn't seem to matter either.

Oddly enough, I jumped on it today to troubleshoot a bit and everything worked as it should. I had forward and reverse in all gears like nothing was wrong. So, I'm pretty sure that eliminates a mechanical issue and I'm dealing with an intermittent electrical gremlin, guessing a sensor or relay.

SN is in my sig.

JD 310SJ Serial #T0310SJ144440

 

[vikingsven]

I did get a code after messing around a bit testing different functions. FLC 1714.07. Something to do with the seat position sensor I believe. Could this be the culprit?

 

[ohdeereme]

Yes, the seat switch could be the problem. You can see the status of the seat switch on the monitor. The 310SJ has two seat switches. One is for when the seat is not in the forward position and the other one is for enabling the secondary hyd. pump when the seat is in the rearward position to supply more flow when running the backhoe.