My '93 Silverado won't downshift on the highway when I floor it (ever since I bought it 2 weeks ago). It kinda revs up a little bit, like it's about to downshift, but then it goes righ back into 4th gear. I went to adjust my TV cable, and found that it was not present. I quote my Hayne's Manual: Beginning in 1991, an electronically controlled automatic transmission, the Hydramatic 4L80-E was installed on some vehicles......bla,bla, mentions nothing about 4L60-E untill.......The 4L60-E and the 4L80-E electronic controlled transmissions are not equipped with a Throttle Valve (TV) cable assembly. The transmission functions normally controlled by the TV cable are controlled electronically... Now, I quote Jimmiee from this page: http://www.gmtruckclub.com/forum/showthread.php?t=22539 So, either: 1. I have a 4L60-E installed from the factory in '93 that needs a new sensor or something electrical 2. I have a 4L60-E (or some random transmission) that somebody threw into the truck last month so that they could get rid of it and didn't bother to put a TV cable on it. 3. Something even stranger (most likely) (truth is, I have no idea) here are the numbers stamped on the sides: driver's side: 43 0923 0403 -and- 8685060 Passenger's side: 5 -and- m30 Please help me figure out what transmission I have, what's wrong with it, and whether I am supposed to have a TV cable. Thanks!