Does any body know the machines for Diffcase machining?
Not for outer operations on diff case but all inner operations like Thrust face, Sperical dia boring, pinionmate boring etc.
I am looking for the machines to buy. Does Turn-mill mchines or SPM is suitable? Who are the machine tool manufacturers for this machining?

On large engines we use a system similar to this one:
http://www.americanmachinetools.com/Line_Boring.htm
It should work for the bores that are in line with the axle. For the pinion bores you can use a conventional milling machine with a boring bar.
If you're doing higher volumes, it may be better to remove the axle housings and machine the center sections on something like a horizontal mill with a tombstone, then re-weld in a jig.