The 4L30-E tranny is definetly of European Heritage. The unit is built by GM of France (go figure?). You might be able to find something on the GM europe web. Personally I can't imagine a tranny that big and tough being used on your daily european driver(which only weighs a few 1,000 lbs and can seat only two with a bag of groceries),but I can imagine it on only the top of the line cars. Check it out.
John