ME29 Differential Lock

[1989Marathon]

I've been throwing around the idea of building a cable operated differential lock for the ME29 transaxle. After looking at the original design of the gearbox, it appears that it is not easily possible to make changes to the internals to make this happen. If anyone has an idea of how to do it internally, I'd like to hear about it. So I started thinking about how to do it from the outside.
Here is my "3-beer" rendering of one possible way. The axle tubes would need to be shortened by the width of the new plates. The gears could be chain driven, or use an intermediate gear. They would be enclosed inside the new plates.
I'm throwing this idea out there so we can all add our ideas.

[nobuckbuild]

Lets first start by eliminating the splined shaft shifting arrangement to an electric pto clutch from a mower so we have no linkage issues and shift on the fly capable system, as far as the axle tubes go i would not cut them down i would just gain the two inches of width on the rear, other than the spring perches needing to be moved you end up with a little more stability on a locking rear but of course then you have the problem of the shaft being to short , is it possible to split the difference or will the the new plate include shaft extentions female from the tube side and male into the diff , also on the axle tube side of things we would also need to a support bearing on the inner axle tube where it meets the new plate for flex support. http://www.surpluscenter.com/1-15T-S...ProductDetails