Slipping Tranny 460E

I have a 1996 g.mc. 5.7 with a 460E transmission and when I am on the throttle less than half way the tranny shifts fine, but when I get on it 3/4 throttle from 1st to 2nd, the engine drops down in r.p.m like its changed gears then 2 seconds later the tranny finially switches gears. Has anyone else heard of this before? Mike

i work at a TRANS SHOP there is a update on that trans (4l60e) do the updated if it still does not work replace the trans with the updated there should had been a recall on that but there was not . the update consists of a few wire to install in the computer wiring

Where can I get info on the update and have you done one?

do the trucks come with tranny cooler??
if not u might want to get one 4l60e's dont take heat to well

If your Revs drop before shifting gears, maybe the engine's not building up power!

Shift your trans into 1st gear, and accelerate while watching your tach
if the engine developes power smoothly without power loss then maybe you really have a trans issue.