A diagram of the 4L60-E transmission is available for download at Grail-SS.com, as of 2015. The diagram is part of the 4L60-E Technician's Guide, and it includes color-coded diagrams of the transmission.
Visitors to Grail-SS.com can click the Tech/Documents link in the menu and scroll down to the 4L60-E Technician's Guide link under the Drivetrain/Transmission heading. Clicking the link opens a PDF version of the guide in a new browser window. The transmission diagram is on page 8 of the guide.
General Motors introduced the 4L60-E transmission to the market in 1996. Experts consider the 4L60-E to be one of the best overdrive automatic transmissions of all time.