I have a 2014 Elantra, 117K, runs great generally. When normal driving, no shift issues. I take a trip once a month to Kansas City from Little Rock.This goes through the Ozark "hills". When the car starts up these hills it downshifts as needed to the appropriate gear, which is usually from 6th to 5th. When its alittle steeper, 4th. The issue I have is when I crest the hill, and either remain level or start downhill, it delays the upshift out of fourth for quite some time. 10-15 seconds at times.If I manually shift it, it is immediate. It seems to only do this when I take a really long trip, doesn't do it on my daily drive to work, etc. Its only the 4th to 5th, works normally from 5th to 6th. Fluid has been changed twice, once at 70K, and again at 100K, using OE SP-lV-M.Other than that, the car shifts normally and when its supposed to. Any one have an idea? (Level check is good). It has done this for awhile (about 40K), and has simply been a nuisance, but lately the time lag seems to be getting longer.