TECHNICAL SERVICE BULLETIN: TRANSMISSION FLUID APPLICATION GUIDE - This bulletin has been revised to include additional information. New/revised sections of this bulletin are indicated by a black bar in the margin area. This bulletin provides information relating to the correct transmission fluid type and fill quantity requirement for each Kia model. A flush is required ONLY when a transmission is replaced, and the transmission oil cooler is transferred to the new transmission.
full bulletin at NHTSA ↗2025 Kia K4 powertrain problems
moderate Owners of the 2025 Kia K4 have filed 7 NHTSA complaints about the powertrain at roughly $2,500 to repair (U.S. federal records, as of October 2026). Source: NHTSA Office of Defects Investigation. See powertrain across all vehicles →
Complaints
7
Recalls
0
Avg fix
$2,500
What stands out
Owners are still filing on this — the most recent NHTSA powertrain complaint for this vehicle was logged 7 days ago.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering powertrain on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
What owners are reporting 2 most recent
I purchased my 2025 Kia K4 in March 2025. Approximately two months after purchasing the vehicle, around May 2025, I began experiencing serious and recurring safety issues. While driving, the vehicle intermittently loses acceleration and becomes unresponsive when I press the gas pedal. When this occurs, I have to pull over, turn the vehicle off, and restart it before I can continue driving. On…
Sluggish acceleration, after I got an oil change a few weeks ago. No warning lights whatsoever, I’m thinking it’s the transmission , taking awhile to speed up especially on highway
Had powertrain trouble with your 2025 Kia K4?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the powertrain problem on the 2025 Kia K4?
It's a documented issue but not catastrophic. 7 complaints have been filed. Repairs average $2,500 and most owners catch it before it causes a breakdown.
At what mileage does the powertrain typically fail?
Mileage data is limited for this issue. Owners report failures across a wide range, suggesting cause is more about driving conditions and maintenance than mileage alone.
What does it cost to fix?
Independent shops typically charge around $2,500 for powertrain repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to powertrain?
No active recalls currently cover powertrain issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2025/Kia/K4.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.