Are your shimmed diffs locking too much?

[TanDaMan99]

I recently installed a J30 Diff with just a single .80mm shim. The smallest one, the first stage that all the write-ups claim to feel like a 1.5way diff. When everything was buttoned up and I tested it out and it was fully locked. The tires would squeeling or hop at every turn no matter what speed or angle.I heard that you have to break it in and do some figure 8s in a parking lot or the like to loosen it up a bit. But I've been doing it all night and the wheels will not give AT ALL, and I mean NONE. It's feels like a completely welded diff now, and as fun as that is, its my daily driver and I need a little give.So I guess my question is if this is just the way it is initially and to just give it time, or is this oddly too much lock? And if it is just a break in period, just about how long is it?