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 ↗2015 Kia Forte powertrain problems
severe Owners of the 2015 Kia Forte have filed 17 NHTSA complaints about the powertrain, typically surfacing around 75,000 miles at roughly $2,500 to repair (U.S. federal records, as of July 2026). Source: NHTSA Office of Defects Investigation. See powertrain across all vehicles →
Failure mileage
Complaints
17
Recalls
0
Avg fix
$2,500
| Model year | powertrain complaints |
|---|---|
| 2011 Forte | 19 |
| 2012 Forte | 10 |
| 2013 Forte | 9 |
| 2014 Forte | 16 |
| 2015 Forte (this page) | 17 |
| 2017 Forte | 11 |
| 2018 Forte | 8 |
| 2019 Forte | 46 |
1crash
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.
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.
full bulletin at NHTSA ↗TECHNICAL SERVICE BULLETIN: TRANSMISSION FLUID APPLICATION GUIDE - 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, refer to applicable vehicles in the chart starting on page 2.
full bulletin at NHTSA ↗TECHNICAL SERVICE BULLETIN: - TRANSMISSION FLUID APPLICATION GUIDE - This bulletin has been revised to include additional information. 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, refer to applicable vehicles on page 2. Refer to the shop manual on KGIS for the specific Kia model for the correct transmission fluid check/fill procedures.
full bulletin at NHTSA ↗TSB: 6-SPD. A/T ADAPTIVE VALUE RESET /RELEARN - THIS BULLETIN PROVIDES THE PROCEDURES NECESSARY TO RESET AND RELEARN THE ADAPTIVE VALUES AFTER TRANSMISSION REPLACEMENT OR REPROGRAMMING/REPLACEMENT OF THE PCM/TCM. AFTER THE ADAPTIVE VALUES ARE RESET, THE TRANSMISSION COMPUTER ADAPTIVE VALUES MUST BE RELEARNED BY DRIVING IN A PRECISE MANNER TO TEACH THE COMPUTER THE PROPER SOLENOID DUTY AND LINE PRESSURE FOR THE NEW TRANSMISSION/COMPUTER COMBINATION.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
The 2015 Kia Forte powertrain complaints center on three major systems: engine, transmission, and ancillary controls.
Engine failures dominate the narratives. Owners describe loud internal knocking and clanking starting around 131,000 miles, with check engine lights and loss of power. Diagnostic codes P1326 and misfire codes point to rod bearing wear. Oil consumption is severe—one owner found zero oil despite recent service; another's vehicle burned through 4 quarts between visits. These failures progress to full seizure or stalling, sometimes without prior warning. Dealers occasionally dismiss early knock as normal, and one owner reported a technician told them knocking was expected.
Transmission problems include sudden complete failure during highway driving and delayed shifts with RPM surge to 3500–4000 before engagement. One owner had the transmission fail twice and paid for both replacements out-of-pocket after Kia declined the first claim. Another found transmission case corrosion at just 5,000 miles.
Secondary issues include unintended acceleration when shifting to Park (causing two crash incidents), engine stalling in low-speed traffic despite oil pressure valve replacement, and emissions system faults following a recall software update that were never resolved.
Kia's response has been inconsistent. Some owners were denied warranty coverage; others found their VINs excluded from class-action settlements despite identical engine types. One dealer performed an emissions recall update that left the vehicle smoking and burning oil afterward.
Same Kia Forte powertrain reports on nearby years: 2012 · 2014 · 2017
Failure modes owners describe
Rod bearing wear and engine seizure
Rod bearings fail due to wear, causing internal engine damage, rattling, loss of power, rough idle, and eventual seizure. Oil loss is frequent. Owners report loud knocking/clanking noises, check engine lights, and sudden engine stall. Some vehicles enter limp mode due to power loss.
When: 131,000–180,000 miles; some owners report no warning until failure
Symptoms owners cite: Loud clanking/knocking noise from engine; Check engine light (CEL); Loss of power and rough idle; Engine stalling or entering limp mode; Oil burning and loss of oil; Misfire codes detected; No warning indicators in some cases
Codes mentioned: P1326, Misfire codes
Repairs/costs cited: Engine replacement required. One owner's dealership estimated diagnostic cost at $134.98 before tear-down. Another owner cited independent mechanic recommendation: oil pan removal or full engine replacement. Multiple owners paid out-of-pocket for replacements.
Recalls/TSBs owners mention: Kia class-action settlement addresses rod bearing wear in 2.0L/2.4L engines (2011–2015 models). However, some VINs excluded from recall coverage. Dealerships sometimes dismiss knocking as normal, fail to document complaints, or deny warranty coverage claiming maintenance issues. One owner reported Kia stated it would not cover repairs despite known issue.
Transmission failure and shift delay
Transmission fails suddenly during driving or shifts improperly with RPM surge and delay. One owner experienced transmission failure twice, both while driving uphill. Another reports delayed/hard shifts and poor fuel mileage. One case notes transmission case corrosion and damage at very low mileage.
When: As early as 5,000 miles; repeated failures observed at unspecified higher mileages
Symptoms owners cite: Complete transmission failure while driving; Delayed gear shifts with RPM surge to 3500–4000 before shifting; Hard shifting feel; Poor fuel economy; Transmission case corrosion and damage; Vehicle lunging forward when shifting to Park despite brake applied
Repairs/costs cited: Owners cite full transmission replacement. One owner replaced transmission twice out-of-pocket due to Kia refusing warranty coverage for first failure. Another reports transmission case corrosion present at low mileage requiring replacement.
Recalls/TSBs owners mention: Kia denied warranty coverage on one owner's first transmission failure, claiming nothing could be done. No dealer-issued TSBs or recalls mentioned in narratives for transmission issues.
Excessive oil consumption and burning
Engines burn oil rapidly, leading to low or zero oil level even after recent oil changes. One owner reported finding no oil on the dipstick; another added 2.5 quarts during a routine visit. Oil loss occurs without visible leaks in some cases.
When: Varies; reported at 91,000 miles and higher; some owners unaware until warning appears
Symptoms owners cite: Oil level dropping rapidly despite recent oil change; No oil detected on dipstick; Loud clanking when oil is absent; Engine knocking/pinging due to oil starvation; Burning smell from engine
Repairs/costs cited: Oil added by mechanics during diagnosis. One owner added 4 quarts after discovery of zero oil level. Long-term solution typically engine replacement.
Recalls/TSBs owners mention: One owner received an emissions/engine recall notice and brought vehicle in; recall service performed, but excessive oil burn issue persisted and was not rectified. Owner concerned about fire risk.
Check engine light, emissions, and diagnostic issues post-recall
After emissions recall software update, owners report check engine light, engine smoking, strong fuel smell in cabin, and diagnostic failures. Dealer diagnostics run multiple times without resolution; replacement parts (gas cap) ordered late or not ordered.
When: Immediately after emissions recall update (around 07/18/19 in one case); symptoms recurred within days
Symptoms owners cite: Check engine light illumination; Engine smoking with burning smell; Strong engine fumes in cabin vents; Engine light returning after partial repairs
Repairs/costs cited: Gas cap seal replaced; diagnostic part ordered but delayed or not delivered. Owner's vehicle remains unresolved after multiple dealer visits.
Recalls/TSBs owners mention: Dealership performed emissions update per recall notice. On subsequent visits, technician stated could not find cause; later identified small leak (suspected gas cap). Multiple diagnostic runs ordered but parts not in stock for weeks.
Unintended acceleration when shifting to Park
Vehicle lunges forward and accelerates despite brake pedal being depressed when shifter moved from Drive to Park. RPMs increase unexpectedly. No warning lights precede failure. Two crash incidents documented.
When: At approximately 20,568 miles
Symptoms owners cite: RPM increase when shifting to Park; Vehicle lunges forward despite brake applied; No warning indicators illuminated; Uncontrolled forward motion into fixed objects
Repairs/costs cited: Body shop repairs completed after two crash incidents. First crash into pole caused minor front-end damage (no airbag deploy); second crash into banking facility at high speed deployed airbags. Both occupants hospitalized for evaluation.
Recalls/TSBs owners mention: Kia dealer stated no recalls associated with this failure. However, one service technician told owner they had heard of this failure occurring before. Manufacturer not formally notified by dealer.
Engine stall during low-speed driving
Engine cuts off completely while driving, particularly in stop-and-go or low-speed traffic. Mechanic diagnosis indicates no oil pressure reaching engine. Oil pressure valve replacement does not resolve issue.
When: Ongoing during low-speed/stop-and-go driving; timing of initial onset not specified
Symptoms owners cite: Engine cuts off mid-drive; More frequent in low-speed or stop-and-go traffic; No oil pressure to engine
Repairs/costs cited: Oil pressure valve replaced but issue persists. No further diagnostic or repair outcome provided.
Synthesized from 17 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 0 most recent
Had powertrain trouble with your 2015 Kia Forte?
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 2015 Kia Forte?
It's a meaningful issue. 17 complaints have been filed and the failure mode causes operational problems for owners. Repairs average $2,500.
At what mileage does the powertrain typically fail?
Across the 10 complaints that reported odometer mileage, most powertrain failures cluster between 30,000 and 91,000 miles, with the median around 75,000. A quarter of owners report trouble before 30,000; a quarter make it past 91,000. Maintenance history matters more than the odometer alone — this is the reported failure window, not a guarantee.
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/2015/Kia/Forte.
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.