Hi
I have an 2006 hyundai elantra with 100k miles on.. Driving it when I get to 30-40 mph the transmission lunges or slips after that happens there is no problem cruising over 50 mph.The fluid is full... Is there an easy fix?? Thanks

Try changing the transmission fluid (Mobil 1) and filter:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-10.html#post1873132

Afterwards, disconnect the negative battery cable overnight, to force the ECM to relearn shift points.

If you haven't taken care of the transmission, up to now, it may be too late for a miracle.