Traction ehydro 3520 will not go into foward or reverse

[snoopygarcia792]

I have a John Deere 3520H 2005 model no cab tractor that has the eHydro transmission. The tractor will not move forward or reverse. I can move the shift lever to A, B and C positions with a slight detent.

I checked the seat, break switches all good. I made jumpers to eliminate them as well. There are no Codes?Hydraulic level is good with new filter and fluid.I clean the Charge flow filter as well.

I purchased the service manual to trouble shoot but not having too much luck.With the machine off I Pulled the X27 connector that goes to the forward and reverse solenoids, both had approximately 4 ohms of resistance. When the machine and either forward or reverse is pressed I get 0 to 3.8 vdc. So it looks like the pedal circuit is working. I tried getting the raw data using the display using the display switch and the turn signals switch but my model doesn稚 seem to work. I am truly lost.

On a side note the power steering works,loader and PTO work fine.

Does anyone know what voltage the forward/reverse solenoids operate at is it a square wave or just a dc voltage? What痴 suppose come out of the A2 electronic drive controller for these solenoids,12vdc a square wave with a different voltage?

Thanks in advance SG792

 

[oldnslo]

If tehse are propostional coils thye are milli-amp control so unsure of the voltage you would read.

 

[jenkinsph]

That happened to me when my 4520 was new, it lost the computer program. Dealer had to reload it at my place. Caused by a faulty ground strap between the computer and chassis. No problems since.

 

[Oldtink]

I don't understand why a fault code isn't displayed with the tractor running first of all.

 

[Spindifferent]

Hi SG792,

Could you share with us if this issue has been resolved? Curious to know in case it happens on my 2005 3520.

 

[jdzaya]

Something similar happened to my 3720. I was flail mowing and a dead strand of golden rod or something went up under the hydrostatic pedals, I could move forward but no reverse. I pulled the stick out and everything was fine. I have no idea what it was touching? The pedal would go down, just no movement. Maybe the stick was hitting a sensor of some kind?

 

[pmsmechanic]

I had this problem as well on a 4410. The seat switch a gotten jammed and no longer made connections. Symptoms were no forward or reverse and the tractor would shut off when the pto knob was engaged.

Went back and read your 1st post. You've already checked this