Here's the tool that my stepdad built after we looked thru many books, forums, tool sites, & more. The one already posted in this thread will only work on the older 700R4's (87 & Back) from what we can tell. This was based on the 2 or 3 early 90 models that we have which do not have the groove/slot behind the splines and finding a factory tool using the same principal as this one designed for the 4L60E's.