Good to hear things seem under control.
I assume the centre pulley mustve stripped when the diff broke, i assume the diff bound up a little like a spool.
So with the bulkheads did you get the new or the old ones? As mentioned the old ones can be used left or right while with the new ones there is a specific right and left bulkhead which must be used on the right side.
I suspect that using the 3racing aluminium diff holders may get around the problem though.
Did you also get the 3racing motor mounts? cause yeah they are narrower than the standard plastic and aluminium ones, so you have to remove the big spacer, but then that leaves a fair amount of slop
