2008 Hyundai Sonata transmission problems

Filed Apr 25, 2025 · Engine, Transmission · VA

Bought in 2023 @ 98k miles. Have had trouble with 1.it would only start in drive, then that seems to have self corrected. 2. In drive, car would not accelerate properly, and would slow as though I was braking, but no foot on brake. Had rear brake sensor replaced, seemed better for a while. 3. Developed oil leak at 120 miles which valvoline characterized as "not serious...just keep checking it and topping it off." So, have been doing that. Today after oil change, it began running rough, lots of vibration, then the shifting problem, sluggishness, and new..smoke from under hood on driver's side. No check engine lights at all. Nothing registered as hot or overheating. Turned off car, checked oil and trans fluid, both in proper range for warm engine. Let car sit and cool for an hour. Decided I had parked too close to the propane tanks for a smoking car, so I decided to start car just to back it into a space across the lot. Car had no issues- No smoke, no jerking or vibration, no sluggishness, no phantom braking. This car has done this same thing about once every 6 months since I've had it. Changed a tire sensor, that seemed to fix it once. Stopped using cruise control altogether, that seemed to help once. My brother is an ASE certified high school auto mechanics teacher who ran his own shop for 20 years and worked on trucks for VDOT for another 7 years and he cannot diagnose it. I know it has something to do with not being in the correct gear, but it's not reliable, and I have a hard time believing it's just my vehicle.

Filed Mar 31, 2019 · Electrical, Engine · 152,800 miles · TX · 1 injury

2008 hyundai sonata 6cyl dohc 3.3l / 152812 water pump went out. Replaced it. Then water ended up in the oil that got into the lifters. Ended up getting another motor. Then my A/C stopped working (didn't blow cool or cold air). Changed oil and oil filter myself along with the oil sensor ( connected to oil filter spot) that was leaking bad as long as the car was running.I was driving on the interstate, in front of a loaded 18 wheeler, driving 75 then my car jerked real hard then dropped down to 40. I had to pull over illegally to keep from getting hit by the truck. As I was catching my breath I turned the car off. When I started it back up it made a weird tick noise. Haven't heard that noise since. When I pulled off it hesitated to change gears from 2 to 3. It finally changed and did not come out of 3rd. Got it towed home. Had my moms boyfriend to check the transmission. He drove it and it was fine. Next morning started car and it sounded like a vacuum cleaner. (low volume) finally it went away. When I headed to work, it hesitated at first. The vacuum noise came back and was louder. Then I sped up to 50, it hard jerked again, and stayed in 3rd gear. As I went further loss power in inside lane of highway and car was smoking under the hood. Like it didn't know I was pushing the gas pedal. Started shaking at around 20 miles an hour. Pulled over and check engine light came on. Called a friend to pull me back home. It was reversing fine but would not go forward. So I changed the accelerator pedal sensor (whole pedal) that wasn't the problem. So then I changed the entire fuel pump/ injector. Still have all parts by the way. That wasn't the problem either. Put it on the machine and it gave a code for ECM and oxygen sensor. Esc light came on as well as TPMS, when I started the car. I could move forward but it was like I wasn't. This all started in february 2019

Filed Apr 8, 2017 · Engine, Transmission · 116,630 miles · MN

Loud knocking sound from under hood. Gets louder as engine heats. Unsafe to drive

Filed Jan 3, 2015 · Engine, Transmission · 139,881 miles · VA

When vehicle is started from a cold start, there is a noticeable rattle coming from engine that lasts about 3-7 seconds. Also while accelerating, the rattle is persistent with throttle input. I was told that the problem is the timing chain tensioner and that the hyundai sonatas have defective timing chain tensioners. I went to the hyundai dealership and they quoted me $1,100 to fix the problem and made me aware that there was a tsb but not a recall on the part even though there is a revised tensioner. This is a ongoing issue and a hazard because the chain could have to much slack and cause the the timing to be off and future damage for the engine.

Filed Nov 30, 2014 · Driver assistance, Electrical · 104,743 miles · WA

Esc light on along with check engine....need push button and turn off engine a couple of time.

Filed Oct 3, 2014 · Engine, Transmission · 149,000 miles · FL

Engine failure -lower rod bent no cause by operator car well maintained.

Filed Sep 12, 2014 · Engine, Transmission · 143,056 miles · CA · fire

Driving while using cruise control at approximately 65 MPH the check engine, air bag, and e.s.c light illuminated. Also, a simultaneous internal engine explosion resulted in an instant fire as well as a rod thrown from the vehicle damaging block and setting the car on fire from a resulting massive oil leak. There was no prior damage leading up to the incident nor any indication to my knowledge that there were any concerns with my car till it was too late unfortunately.

Filed Jan 9, 2012 · Transmission · 61,500 miles · NY

While stopped at a busy intersection, with engine running and clutch to the floor (disengaged), the car began to lurch against the brake. The clutch began engaging by itself because the concentric slave cylinder had failed at 61,500 miles. The dealer advised the car was 1,500 miles out of warranty, total cost to repair was $1950.00 and 3 days of service. Because the leaking hydraulic fluid "soaked" the clutch, the $794.00 clutch/pressure plate needed replacement as well. Hyundai will not honor any "goodwill" adjustment.

Filed Nov 17, 2009 · Transmission · 34,000 miles · CT

Went to dealership and advised of a transmission problem. Supposedly a service flag was sent to dealerships and just "flush" the transmission. 5 days later and 550 miles from home, the car broke down, was towed and advised I needed a new transmission. Still sitting out of state waiting for the part to arrive.

Filed Jun 16, 2009 · Electrical, Transmission · 43,000 miles · LA · fire

Tl*the contact owns a 2008 hyundai sonata. While driving for approximately three hours, the contact noticed that the trunk ajar warning light was illuminated on the instrument panel. Another motorist alerted him that the rear of his vehicle was on fire. The contact pulled over and noticed that the wires in the trunk were on fire. He was able to safely extinguish the flames and resume driving. While driving 40 MPH in third gear, the vehicle unexpectedly downshifted to first gear. In addition, the engine warning light illuminated on the instrument panel. He is in the process of having the vehicle inspected to determine the cause of the failures. The failure and current mileages were 43,000.