4120 Shuts down while operating

[jsvidrine]

Hello;

I have a JD 4120 W/ Power Shifter bought new six years ago. Over the weekend i started having problems with it just shutting down, like when you get off the operator seat while in gear.

After jiggling the power shifter or the PTO button, it will start again, this went on for a long time but only while and each time the tractor was in motion.

I think it might be a safety switch, anyone else have something like this happen?

Thanks
Jv

 

[AKfish]

Hello;

I have a JD 4120 W/ Power Shifter bought new six years ago. Over the weekend i started having problems with it just shutting down, like when you get off the operator seat while in gear.

After jiggling the power shifter or the PTO button, it will start again, this went on for a long time but only while and each time the tractor was in motion.

I think it might be a safety switch, anyone else have something like this happen?

Thanks
Jv

Me thinks you've already diagnosed your problem... If you don't have the Technical Repair manual to help you with tracking down (and testing) the safety switches (I'd buy one) but, you can get detailed schematics from JDParts.com that can get you started, at least.

AKfish

 

[jsvidrine]

Thanks

 

[jsvidrine]

Update;
Asked my dealer if any of his other customers were having similar problems ;
other than the shut off, (1) would not starting or showing any power in the dash unless i pulled pulled the PTO switch, then the tractor would turn over start, (2) after a few minutes running the Low fuel warning / alarm would come on a stay on, (2) the indicator would not come on showing the tractor was in 4 wheel drive.

Dealer tells me must be a bad connection, i should look on the firewall under the hood and unplug and re-plug all the connections on back of panel, well he was wrong about the location, as you all already know i had to remove the hood, crowel and bottom wrap around to get access to the back of the display when i did I unplugged and replugged each one at a time, now i have to turn the light switch to the hazard light position for the engine to turn over, but it won't start.

I have 130 hrs on the tractor but it is no longer under warranty and before i go back to this guy i was hoping to know a little more about what the problem is.

I have also removed the display (PN LVA12705) and was wondering if anyone knew where i could send it to have it diagnosed, it looks like a very expensive piece

thanks
john

 

[Bigfoot62]

John,
You will have to call and ask if he will do it or not. I know that he rebuilds/repairs the instrument cluster on GM trucks.
The Turbo Shop
115 Main, Blanchard, LA 71009
318-929-7141

If he can't do it, he might could direct you to someone who can.
Hope that helps.

 

[Ken]

Hello;

I have a JD 4120 W/ Power Shifter bought new six years ago. i started having problems with it just shutting down, like when you get off the operator seat while in gear.

After jiggling the power shifter or the PTO button, it will start again, this went on for a long time but only while and each time the tractor was in motion.

I think it might be a safety switch, anyone else have something like this happen?

Thanks
Jv

I have a 4520 Power reverser so maybe not same problem . Mine will die when getting off the seat to open gate or just stand up but will not restart instruments dead.
Nothing located until one day touched a sensor under the deck near clutch rod going into the flywheel housing. heard a click in dash area. engine started as normal . but then again would quit same fix to get running again took to J.D. service dept. and they changed out sensor. worked for a while then again had to jiggle the connection to restart the engine. re crimped the connector and tie wrapped the wire to the sensor and now for 4 years no problem with this area.

May not be your problem but wouldn't hurt to check if you have similar wiring.
ken

 

[jsvidrine]

thanks Ken and bigfoot62. I will check out the safety switch and I will check out and clean the ground wire to frame connection. If neither work i will call the turbo shop
Jv

 

[jsvidrine]

Update: found the MWD (4X4) sensor switch plug loose and slightly backed out under the tractor. Pushed together and tie-wraped the connector to prevent it getting loose again. Cleaned the ground point and put everything back together and tractor started right up, even the fuel gauge works!

Thanks everyone.

 

[Ken]

Update: found the MWD (4X4) sensor switch plug loose and slightly backed out under the tractor. Pushed together and tie-wraped the connector to prevent it getting loose again. Cleaned the ground point and put everything back together and tractor started right up, even the fuel gauge works!

Thanks everyone.

Good you found a positive problem ands good fix to the repair.

Ever wonder why the things easy to get ripped loose or broken off is on the bottom side of a tractor?

Did the design engineer ever use a tractor in a day by day real work being done field?

The testing in a building dust free and highly polished floor next to a coffee bar. wonder why nothing ever broke. Like the reports after the tractor was sold to the public.
ken

 

[csherron]

I have a 1968 John Deere 4520 syncro shift, it has started shutting down like it runs out of fuel. Give it maybe 5 minutes and restarts with no problem.
Started out losing power like it was missing while bush hogging. Replaced the fuel filters to start any more ideas?

thanks
Chris

 

[beenthere]

Clean the fuel line and fuel tank. Check fuel line for crud or breakdown of hose material. For starters..

 

[kwbretired]

Check the fuel cap to make sure the vent isn't plugged.

 

[dothatagain]

Hello;

I have a JD 4120 W/ Power Shifter bought new six years ago. Over the weekend i started having problems with it just shutting down, like when you get off the operator seat while in gear.

After jiggling the power shifter or the PTO button, it will start again, this went on for a long time but only while and each time the tractor was in motion.

I think it might be a safety switch, anyone else have something like this happen?

Thanks
Jv

My 4120 was also stalling at random times; complete power loss. A hard hit on the dash would restore power most of the time but depending on the day it might try to shut down 12 times in a row or not at all. I finally tore into the dash. When I did this, I couldn't get any power to the starter. After reading other posts on this forum, I turned on the lights and attempted to start; it cranked but wouldn't turn over, just as reported by another person. I continued to check electrical connections and eventually found a connection behind the dash that was apparently loose enough have caused all the problems. It appeared to be a good connection, and all of the clips were still in place. I just pushed it tighter, and this seems to have fixed my problem. Getting behind the dash was a headache, but this ended up being a no cost repair.

 

[beenthere]

Sounds like you have it fixed.
Welcome to TBN, and good to have you letting the forum know your results.

But am some confused:

cranked but wouldn't turn over

That to me is an oxymoron.. if it is cranking, then the engine is turning over. Maybe not running, but at least is turning over.
Or are you saying the engine is locked up?

Or have I been missing something over the last 70+ years.