new to this so bear with me! i have a 1996 silverado z71 offroad with a 5.7 ltr. engine ,4l60e trans. the other day i'm driving 20 mph in 2'nd gear i stomp the gas to pass trans downshifts like it's supposed to but when it started to upshift to previous gear i heard a seat jarring bang. ok i figure seriously hard shift untill i try to pull off from the light to realize i have no gears. ok so i rev to about 4500 rpm and truck starts to creep real slow like it's low on fluid. not the case! i have since removed & broken down trans to find no dammage. could someone please give me a clue? thanks.

 

hmmm...thats odd. when mine did that, i had broken the output shaft and taken out the planetaries. good luck with it.