Hi everyone I just joined up here and have a question regarding my automatic transmission in my '01 C5.

What is happening recently when I'm driving over 50 MPH 4th gear won't engage all the time. Or 3rd gear is sticking? What happens is RPMs will get high as its stuck in what I believe is 3rd gear. I then feather the gas and most times it will up shift some wheres between 20 secs to what seems like almost a minute?

I'm not really a transmission guy so what advice can you give me? Thanks for the help.

Joe