Traction Problem with load mode 4120

tschwerm · Sep 25, 2011

Have a 4120 and when i switch the load switch to the on mode the drive doesn't move the tractor unless you run the tractor at above 1500 rpm is that normal?

fuseboxer · Sep 25, 2011

Load match is a mystery to me I will be looking fwd to expert knowledge imparted in your thread. I think of it as an improved CPU controlled governor. The old style mechanical governor is not on our units. If you push load match on with the RPM at low idle and the engine not running when you start your tractor do you find it a nice anti-theft feature? Will not move? I think I have experience this but not totally sure. Using the search engine of the old threads on load match is interesting.
Scooping dirt with my 300CX with load match in the off position and the trans in the "A" position my RPM's can drop some. With the load match switch turned on the RPM's and probably the torque stay constant sounding.

fuseboxer · Sep 25, 2011

Just got back in from out side playing with the tractor in the different gears and with and without Load match on. It likes the lower gears and higher RPM but will move at idle in all three gears with load match on. What I believed that it would not move I could not replay. Must have been in netural.

tschwerm · Sep 25, 2011

Thanks for the input fuseboxer I remember when I got the tractor about a year and a half ago that it did run even at idle. I was working on my sisters horse ranch where she had about 100 trees to clear and put it in the load on position and it would not move.

tschwerm · Sep 27, 2011

UPdate I had the JD dealer out today to check out the load match mode.

Worked on it most of the day could not figure out the problem. he decided to recalibrate the sensors . tried many times but the tractor would not calibrate.

now it doesn't move at all.... this is horrible I am not happy. now he is thinking it might need a new control module... 580 bucks..

Any one have any ideas???

fuseboxer · Sep 28, 2011

You wrote: now it doesn't move at all.... this is horrible I am not happy. now he is thinking it might need a new control module... 580 bucks.

Having a JD tech on a house call is like having a medical doctor making a house call with advice. Very few people are going to offer advice, many that post on tractorbynetare are JD tech's or connected.
I assume he is comming back with a CPU in the near future. I am supprised the tractor was not taken to the shop.

Be sneeky and reset your CPU and when he comes back before he swaps out your CPU for the big charge have him try to calibrate once more.
I believe if you disconnect the battery Positive for a Minute then reconnect the memory error of the cpu may clear. Let me know if you tractor at least moves after you disconnect the battery. Leave to Load match on off.

tschwerm · Sep 28, 2011

We did disconnect the battery but not for 1 minute. I then turned on the ignition while the battery was disconnected thinking if there was any charge left in the module turning on the ignition would discharge the module capacitors
I think it did because the start up sequence seems quicker.

fuseboxer · Sep 29, 2011

Too bad they do not give a credit for your old CPU. Your JD tech is the way to go you tried the best you can. Was you tractor left on top of a hill in a lightening storm? When you use search on tractorbynet ,CPU, many threads but did not see confirmation of replacement. JD mfg does a good job sealing up the CPU and having a triple seal on the grounded massive plug. The whole unit is sealed in a can. When I took mine out to examine I question if it has the ability to withstand an "electro magnetic pulse ".

tschwerm · Sep 29, 2011

Tomorrow the replacement module should arrive at the dealer. They winched my tractor on a truck and hauled it back to the dealer yesterday. they claim they may have it back to me before the day is done....we will see. They are trying.