B7510 Diff Lock Story

[Trent]

I have only a few hours under my belt with the tractor, but would like to share my experience with it.

Before finalizing my purchase on the 7510, I had read about some occasional sticking of the diff lock. I went to the dealer and asked to check the machine over and drive it again. The tractor had about 440 hours, looked clean and lightly used.

My check out started with the diff lock on my mind. After looking things over, getting the machine running, and slowly moving forward, I stepped on the diff lock pedal and it felt like there was no movement at all. About the same time, I was met by a service tech that asked, "are you having problems?"I told him what I was doing and he said the diff lock has probably never been used and most people don't know what it is. I assumed the linkage was stuck and still committed to buying the tractor. The first day or two after getting the tractor, I checked out and lubricated the linkage.

After running the machine for a few hours, I still approached the diff lock issue very carefully, as I did have it get stuck engaged a couple times.

My strategy to safely get the mechanism working:
After working the tractor and knowing everything is warned up good, I shut it down and jack up the left rear wheel, put shift lever in neutral. With one hand on the tire, and one on the diff lock pedal, I slowly turn the tire and slowly work the pedal down until I know it is engaging a little. At this point, rolling the wheel the opposite direction just a bit. Doing this Lets me know it should be free to engage. At this point, I don't move the wheel any more. Being careful not to push too far, I begin to gently work the pedal up and down. The first time I tried this, it stuck and it took me awhile to free it up (I think the tractor was cold). Now, after doing this several times, I have been able to get more aggressive, and work the pedal quickly up and down with my foot.

Seems like it may be OK and continue to free up as I use it. Certainly a needed feature on uneven ground!

The forum has been great and so has the tractor!

Trent

 

[hodge]

Warm or cold probably doesn't affect the diff lock.
Sometimes it won't engage, not because there isn't a problem, but because the lock pins aren't lined up to engage until the position of the diff case changes. That is why it isn't supposed to be engaged when the tires are spinning- when the pins do drop in, they can shear off if things are spinning and under power.
When the diff lock isn't used, things get stiff. I use mine on a regular basis, and it still gets stiff. I've found that where the shaft goes through the axle case is where it gets tight- if I keep that lubed with some penetrating oil, it stays free. I'm sure debris like dust and grease migrate in there.
Jacking the tractor up and spinning a tire is a great, gentle way to get things more limber- good idea.

 

[Tooljunkie]

My diff lock gets this way too, as well as my brake pedals. A little spray and its back to normal

 

[Asok]

I had the same problem. 25 year old tractor, only 400 hours, probably had not moved in a year or two. Diff lock would not engage, then when it did, stuck on. I had to manually force the linkage the first time. I have used it a few times since then, works great now.