To the best of my recall, I have never successfully engaged the Diff Lock while standing still. I always have to move the tractor.
I do find it odd that such a simple one-line explanation was not in the manual.
It seems to me it's like shifting gears on a manual transmission without a clutch. I drove a VW Bug that way for some several months. The clutch was shot so, I just didn't use it. After a while, I got rather good at never grinding the gears.
The diff lock pedals on my tractors aren't a direct linkage, they're basically a pedal pulling on a spring pulling on a linkage, so you can push the pedal, but the linkage won't actually engage the locker until the elements line up.
I agree this got into splitting hairs. Sure it won't work if you're sitting still 90% of the time unless you just go lucky and everything lined up like winning a slot machine, but the main point is stuff should not be moving fast, with a lot of momentum, or with a lot of power behind it when the mechanism engages.
Also, most manual transmission gears are synchronized, and most people who think they can 'float' gears well don't realize the extent to which their synchronizers are silently converting to powder to cover for them.
On a related note, most manual transmissions have un-synchronized reverse gears. Like a tractor, quite often the teeth of the gears do not line up to engage properly when everything is stopped. If we take things in this thread purely literally, it would seem a lot of people's solution to that would be 'just keep pulling on the shifter and let out the clutch, it'll pop in!' and we can all imagine how great that would work. But the reality is that a nuanced version of that which is just a lot longer to type out, is in fact what everyone does, and is in fact fine to do. Apply a reasonable amount of torque, at a reasonable rate, allowing the pieces to align and engage under low-load conditions, and then resume normal operations.. yep, we're all pretty much doing that.
