Differential Lock on 5600A

[1965tontruck]

While plowing yesterday I had some slippery conditions where I tried to lock the differential for additional traction. I know from previous experience that the steering mode needs to be in 2-wheel steer and the wheels need to be straight before the differentials will lock. So, I set up the machine and had wheels straight, pushed the differential lock button, and to my surprise the light did not illuminate. I can tell you that the differentials did NOT lock. I checked for codes and nothing came up. Where should I start looking for problems?

 

[SSdoxie]

Was the indicator light for rear wheels straight lite up at the time? If the light doesn't come on, it won't engage dif lock. If light does not come on when wheels are straight (visibly looking at them), the angle sensor might be out of calibration.

 

[SSdoxie]

If the wheel indicator light was on and Dif. Lock not working with no code showing, the problem would be in the input side of circuit. Check Dif. lock switch, power supply to it, and power through it back to controller. With no Input voltage/signal the controller doesn't know if you are pushing the switch or not.

 

[1965tontruck]

Thanks Dennis! The wheels were straight and the wheel lights were on.

An update, I had to use again today, so before I pulled out of my barn I tried to lock the differential. To my amazement, it worked. So I was plowing and ran into a condition where I needed the dif locked. No dice - wheels were straight and dif would not lock. I throttled down and checked wheel alignment and yep they were straight. I hit the lock switch and the dif locked. I started plowing again and found as long as motor was throttled up then dif would not lock. If I throttled down then dif would lock. I could maintain lock when throttling up. So it does work, however, I should not need to throttle down to lock difs.