Prior to replacing the automatic transmission fluid (to improve shift quality), make sure that the transmission fluid level is correct. Also, make sure the computer that controls the transmission has the most up-to-date adaptive programming information. When servicing these transmissions be sure to use fluid approved by Hyundai.
Car Problem Reports
Hyundai XG350 Confirm Latest Software For Transmission Control Module and Correct Fuild For Proper Shift Quailty
Hyundai XG350 Problem
Average Mileage: 66,923 mi (34,000 mi - 80,000 mi)
auto shifting is delayed. trans fluid due for change
Visitor, 2005 Hyundai XG350, 80,000 mi
haven't fixed yet
thought it was just due to being in excess of 80k (about when it started). Been dealing with it for over 85k miles now (over 165k on ODO)...
Visitor, 2002 Hyundai XG350, 75,000 mi
Late shifting into third 3rd gear. Changed fluid at dealer. Seemed okay.
Visitor, 2005 Hyundai XG350, 69,615 mi
transmission "kicks" into 2nd gear. coded as "relearned shift values" and they updated the computer system. $50 at the dealer.