JD 425 random diff lock engagement

[JerryLook]

I recently acquired a JD 425 from a family friend. He got an E-mower and gave me the JD.

Anyways, when I’m mowing sometimes the diff lock will engage. I can tell because it starts sliding the front end. Haha. Then if I drive it a little bit there is a clunk and it disengages.

The diff lock pedal itself sits low on the floor board. I wonder if the spring that’s supposed to hold it up is weak.

Attached are pics of how the diff lock button looks as-is, and also when I hold it up with my hand

The mower has been serviced by a JD dealer its whole life. It’s had the trans fluid changed a few times now. Hours are around 1200.

Thanks

 

[Steve in IL]

Sure looks like a return spring issue. Here is a photo of the whole setup from the Deere Technical Manual…

 

[JerryLook]

Ok thank you. Are you talking about this spring or the other one in the pic?

 

[JerryLook]

The part circled in red I have as P/N M117909, and the other spring is P/N M117024

 

[Steve in IL]

I’m thinking it’s the spring you have circled. The other spring looks to just enable for the peddle to be pushed down and create tension on the linkage until the diff lock cog actually engages.