Use a pin punch to tap it out and then go to your hardware store and get another one the same size.
a few years too late but i need one if someone has this type of spacer for my truetrac as it didn't have one in the box it's a solid piece as picturedI have new thrust block from Dr Diff I don't need and never used. I would have needed it for setting axle shaft end play with conventional bearings. However, I bought axles with green bearings instead. If you have green bearings you don't need the thrust block.
PM me if you want it.
I'm sure Dr Diff would have one to sell. I dunno about overseas shipping.a few years too late but i need one if someone has this type of spacer for my truetrac as it didn't have one in the box it's a solid piece as pictured