Not all are the same. It depends on what trans, and if its automatic, or stick, 4x4 or 2 wheel peel. Most common are 1/4x20. 4x4 700R4s are metric, I think they are 12 or 14 MM, don't know the thread count. If I had to guess I would say 1.25, or 1.50.
The dust shield doesn't hold oil in though.