2007 Hyundai Elantra Transmission Problem

No idea but it sounds like it was slipping and this means it’s more than likely fried.

Many people facing an expensive engine or transmission repair often blame the car maker for being responsible for the problem but in many cases the problem is caused by abusive driving habits or not maintaining the car properly.
Automatic transmission fluid should be changed about every 30k miles and only with the proper fluid. Failure to do so can lead to problems.