Is the new differenrial from NorthernTools? If so I'm suprised that the mounting bolts for the sprocket is 1"?? Are you sure, doesn't look to be from the photos. If your old bushings on the old diff are shot and you know the model of the diff I'm sure that PartsTree or OutdoorDistributors carries it. There are several sprockets on Ebay that might fit that 1" spacing? If I can be of help PM me.