transmission slipped 2x shifts fine in manuel
 

Any thoughts on where to start
after transmission slipped one time then froze or got stuck on freeway. Switched to manuel and it worked just fine to get home. Hasent been driven sinse. Should i just drive in manual and wait for it to really seize? Any thoughts on where to start besides going straight to replacing the tranny? Will i damage the car if i continue to drive it after it slipped 2x. Shop found no evidence that it needed a new tranny. Took it in and got it mainentenanced after the first issue. When it happened a 2nd time they said ya most likely needs a new tranny. I know that makes sense its just that i wonder if anything else should be checked first that could be more minor ?? Is it strange that they didnt run codes? Any info any thoughts any replies will help thank you...