You DON'T need high tech tools to do this. Aftermarket gears have the depth measurement marked on them. This number is the measured distance from the machined surface of the pinion gear head, to the centerline of the ring gear. Common sense tells you that the ring gear centerline, is also at the parting line of the caps. So my "trick" pinion setting tool is a precision straight edge and a set of dial calipers. Lay the straight edge across the carrier, place dial caliper on top of straight edge.....roll the caliper until the "tail" contacts top of pinion gear. Read that number, subtract width of straight edge(mine is exactly 1") and there you have it. This and a set of honed bearings is ALL you need.

Now, I have had people tell me the cap parting line is not always "true" center of ring gear, because of casting variance. Ok, I have never seen this to be true, but lets say it is. You can STILL use the straight edge method. It will be really close and you are going to put it together, check the pattern and make adjustments anyway, so what does it matter. This is NO different than guessing at a shim pack you have and checking it, although this will likely be closer from jump, unless you get lucky on the guess.

If you just WANT to buy a tool, but not break the bank. Try the Ratech tool. They are cheap, about 30 bucks and actually work. Look it up. Little different approach, but they work