the e4od is a fairly complex trans inside. its actually exactly like a c6 with an overdrive extra gear. just lube all rubber and seals with vaseline before installation, and soak any new clutches in tranny fluid before installation. i would definitely have a book on hand so you can check all clearances. you may end up needing selective snap rings for some of the clutch packs to get the clearances right. after valve body removal, be sure to take note of where check balls are located. dont want to leave one out. good luck