Poor Shift Quailty of Automatic Transmission on Hyundai Sonata

Problem Description and Possible Solution

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.

Problem Data
RepairPal Verified
Average mileage: 68,325 (3,100–154,000)
Drive Train affected: Automatic Transmission
12 model years affected: 2004, 2005, 2006, 2007, more2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015
103 people reported this problem
Viewing 1 - 20 of 84 comments
I noticed that my car is beginning to down shift with a hard thump at 20mph. Has anyone had this problem?
Hard violent downshifts when drive car while cold. Almost disappears after warmed up. Harder upshift when cold. Will be taking to a dealer to diagnos issue.
HARD down-shift always between 20 - 25 mph.
Last year my Sonata started downshifting when driving on the freeway, on its own. I paid over $100 to get the dealer to fix it. They said it was a software glitch and they fixed it by loading new software. That was 2013. Now (2014) it downshifts hard when I'm braking in city traffic. If I'm going to have to pay this every year, I may be done with Hyundai. Other than this problem, it's been a great car. Hyundai needs to take ownership for this defect.
At times,before reaching normal operating temp.transmission would shift into next gear with a very very hard jerk.This would not happen all the time.Thank you
Hard downshift from second to first when cold.
In cool weather the transmission downshifts with a hard lurch at 20 mph, after warming up it seems to go away.
Sonata Limited.I've had transmission problems starting at about 6 mos. and several times since...ECM & hard shifts, like someone hit me! The ECM should be covered by warranty. Poor gas mileage since about same time but ironically, this specific yr/model excluded from the class-action lawsuit that was awarded. Too many other problems to list. I'm afraid to take on trips, too. What a lemon! I'd never buy another one! Shame cuz a beautiful car...but looks don't make it run and get me where I need to go. Going back to Toyota!
Between 35-45 mph, that transmission has a hard time shifting into the next gear
and makes "growling" sounds as though it is "hung up", but the Hyundai local
dealer doesn't see any problem (this is without the ECO button engaged).
I have a 2009 Hyundai Sonata and experiencing the hard thump when the car downshift to 20 MPH. I am the original owner of the vehicle. Hyundai needs to take responsibility for the defects in their cars.
I have a 2009 Hyundai Sonata Automatic when the slowing down between 30 mph-20 mph the car jerks experiencing a rough down shifting.
Hard down shift from 4th to 3rd gear when cold. Not as hard when warmed up, but still not right. Taking it to the dealership tomorrow...
My car jerks while slowing down, jerks occurs at 20mph, even without applying the brake. My dealer updated the software, only for one month it was fine and again started occurring. Recently had an engine oil change as regular maintenance, worked fine for one month now jerk is again occurring at the same speed.
My 4 cylinder 2009 Sonata shifts hard from 2nd down to first until the transmission warms-up. Sonatas should be recalled for software upgrade. I may wait until the tranny goes then have manufacturer replace under warranty.
Each morning when coming to a stop harsh down shift into 1st gear, but will go away after warmed up. Took into dealership and they did update to ECM, which was not covered under warranty, so much for the 10yr 100,000 mi warranty.
not fixed, I shift into neutral, when coming up to stop signs--Jerky downshift -- if I don't put it in neutral.
Between 30 and 40 miles an hour my car seems to get stuck in between gears, will not move and the rpms go up to 3 or 4. Eventually it catches and accelerates forward. This problem is selective and will not do it for the mechanics who have been trying to diagnose the problem and its not throwing any codes.
At low speeds I get a very rough unexpected down shift. I'm going to have the transmission fluid changed and have the check the software when serviced.
Only happens when car is cold. As I slow up (downshift) to a stop sign, the car jerks forward abruptly.
I also notice a slight slip or lurch when downshifting in the sport mode. This happens at around 20 mph. This problem is intermittent.
Told a dealer where I'm staying in Florida and he said he couldn't find anything wrong. I still am experiencing this issue.