JD6420 randomly shifts to neutral

[TC 40 Chuck]

So, the 'patient' is a 6420 with about 5200 hours that has been commercially converted (Gilbert) to a two track snow trail groomer. Transmission is power quad (16 - w/ 4 power shifts). This thing is a beast with the aggressive tracks & a joy to operate.

It has recently developed a condition where it shifts to neutral. The reverser (I assume) goes to n (& you hit the windshield!), the selector lever stays in F or R. If you move the selector lever to N, then immediately back to F or R, the reverser re-engages and you're back in business. Then it will happen again anywhere from 10 seconds to an hour later. I kind of wish that it would just quit completely as that MIGHT be easier to diagnose.

Anyone have any ideas for me???

Thanks in advance!

chuck

 

[Zebrafive]

Is the control for the Reverser, mechanical or electrical? It sounds like an electrical problem.

 

[Tx Jim]

Sounds as if there's a bad relay.

 

[TC 40 Chuck]

The control is electrical (at least at the steering column).

I was, of course, hoping that this condition might be a common thing with 6420 series & someone here could save me a bunch of time! So - I'll post findings IF I can get it resolved!

 

[Zebrafive]

I was guessing the column control was electrical, not mechanical.
I would start by wiggling the lever and see if it drops from forward.
Also there are relays that could be getting tired. As mentioned by TxJim
Then maybe a loose connector.
Finally solenoids.

My first guess is the control lever is worn and causing the problem

 

[jd110]

The tractor should be storing codes when the fault occurs. Do you know how to read the codes? The most frequent problems are control lever/switch assembly, loose wires, enable sensor and enable relay. Lots of other things can cause it also. If you can get the code, it will point you in the right direction.

 

[TC 40 Chuck]

Yeah, so I forgot that part. It beeps three times and the blue "i" light blinks.

I don't know how to read the codes...

 

[Zebrafive]

Yeah, so I forgot that part. It beeps three times and the blue "i" light blinks.

I don't know how to read the codes...

It's in the owners manual. Section 135 Diagnostic and trouble codes. If you do not have an owners manual, you can find it online line and read it online.