Deere 3R-Series (3033R) Diff Lock issue

[WinterDeere]

Hi folks,

3033R purchased new in 2019. I've used the diff lock only a handful of times, and it's always worked in the past, although maybe a bit more delayed to engage. Always figured it was an issue where the gears had to mesh just right before the pedal would drop and it would lock in.

But today, I got caught climbing a hill with the wheels spinning on only one side and the tractor walking sideways across the hill. Hairy situation, and the diff lock pedal would not depress at all. I was standing on it, going both backwards and forwards, it would not depress at all. I backed down the hill and drove in circles awhile, both 4wd and 2wd, forward and reverse, and the diff lock pedal is locked in the full-up position.

Anyone ever experience this? What's the probable issue? I did get under there and look at the linkage, and there's no obvious external obstruction, at least so far as I could see crawling around in the snow.

Thanks!

 

[RayIN]

Yep, my MF 451 diff. lock pedal would not depress. I inspected everything and noticed the shaft going into the diff was rusted.
I sprayed it liberally with Kroil every evening and tried working the pedal, finally after a week the pedal moved and locked properly.
My tractor has 2 discs that lock together using 6 rectangle depressions on one disc and 6 matching projections on the other disc, both are wet discs.
I use it while tractor is moving, but operators manual says to use when it's not moving for some unknown reason. I guess the writer has never driven a tractor about to get stuck.

 

[beenthere]

WinterDeere
No answer for you, but this link to JD parts I believe shows the 4 pins that lock the diff.
Why you experience your problem, hopefully someone can help.

https://partscatalog.deere.com/jdrc/sidebyside/equipment/3514/referrer/navigation/pgId/9498984

 

[WinterDeere]

I'm about 2 weeks overdue for my regular yearly maintenance, because I have a few other big jobs going thru the shop right now. Hopefully I'll get them cleared out in a few weeks, so I can get this tractor into a dry heated shop for maintenance, and get a better look at the linkage. Otherwise, I'm waiting for a break in the weather, to fight with it in the driveway.

I spent a large fraction of my life building hotrod motors, rebuilding boat motors and outdrives, and doing all my own tractor repair. But I don't have time for any project as big as splitting the hydrostatic transmission case on this machine, right now. If it's anything internal, I'm going to have to find time to schedule a dealer drop-off.

 

[34Willys]

My Kioti did the same thing. Follow the pedal linkage and lube all the joints, but especially where it enters the housing.
I'm 6'3", 215lbs and I could not get it to engage. Sprayed some penetrating oil and it will engage with normal light pressure once the gears synched.

Patrick