Automatic transmission Kickdown

SOURCE: 2001 Hyundai XG300 won't shift past 3rd gear

sorry to say trans is fried.
Consider a used trans from the bone yard
or a rebuilt one.
An independent auto shop is likely to give you a fair price!!!!!!!!!!!!!!!!!!!

SOURCE: Hyundai i30 Diesel automatic won't accelerate above idle at light

DOES THE ENGINE MIL WARNING LIGHT COME ON? WITH OUT MORE INFO YOU NEED TO CHECK MOTOR ON A CODE READER FOR STORED FAULTS, CHECK ALL AIR LINES TO EMMISION CONTROL, , SOUNDS LIKE YOU HAVE GONE INTO SAFE MODE, A SPLIT OR LEAKING PIPE ON THE INTERCOOLER IS A COMON FAULT ON THESE, IF YOU SWITCH ENGINE OF AND BACK ON QUICKLY WITH MOTOR RUNNING WITH OUT STALLING MOTOR AND IT CLEARS THEN IT IS PROBERLY THE SAFE MODE CUTING IN MEANING A FAULT HAS BEEN SEEN BY PCM

Testimonial: "Thanks.Didn't notice any engine lights came on. I had a problem free day today, but if it happens again will check warnings and PCM computer check"

SOURCE: 2004 Hyundai Elantra GT (manual)Loosing speed/power while driving

tranny si sliiping due to worn clutch disk you will need to have it serviced / rebuilt

Testimonial: "Thank you so much for your feedback."

SOURCE: 2000 Hyundai elantra transmission delay, reverse going

Did you check the transmission fluid level? If necessary, add fluid. However you probably have a more serious problem. Take the car to a qualified transmission mechanic.

SOURCE: I have a Hyundai Avante

The hold bottun is basically a downshift button , just a silly gadget. It will not Damage transmission transmission shifting from drive to neutral , but why would you? Drive the car as it was designed. Owners manuals are copy righted , and are only availiable new from dealer . May try amazon.com or something like that. Have seen them in glove boxes at salvage yards if you got some time and a good pair of boots.Good Luck!