Does not shift, engine light on?

[kudisbetta]

my ls transmission sometimes disconnects on D4. I get an E on the display. on D5 it doesnt disconnect, but it seems like it doesnt shift into the last gear. i am at 3k rpm at 60-65 miles an hour. however sometimes i can fix this problem by going to the triptronic and manually shifting down a gear to over rev, the back up.
Is my transmission done?

 

[NYC LS8]

Get the codes read and find out what the problem is.