strictlypersonl,
Not to be picky, but I just purchased a TKO 500. It has ratios similar to the 3550 (3.27, 1.97, 1.34, 1.00, 0.68). In the following link, it's just like the TCET 4615, except mine's called the TCET 5201, with a 26-spline input and 31-spline output.
http://www.ttcautomotive.com/English/news/20news.asp
Tim