We can commiserate.
Mine stuck in 4th gear on Monday.   Folks have mostly told me not to try to
fix it myself even if I am fortunate enough to get hold of the special tools.
For the time being, I have just gotten hold of a used one with 74k miles.  I
just hope it doesnt go the same way too quickly.
I just dropped my tranny out using a floor jack and some blocks of wood.
Van is on axle stands.  One of the easiest tranny removals I have done.   It
is heavy though.
I had to remove the starter and lay it on its side to get it out from under
the van easier.

Is there a way to forestall the slider breakage ?  Using Redline oil so there
is less effert needed to change gears perhaps ?
good luck,
Steve Cotsford