This Preliminary Information communication provides information to the technician on the steps to diagnose and repair vehicles that may have a Service Engine Soon Malfunction Indicator Lamp on at low mileage. Technician may find Diagnostic Trouble Codes P0420 and or P0430 stored. Technician should be advised that the catalytic converter efficiency Diagnostic Trouble Codes P0420 and P0430 are disabled for the first hour of engine run time to allow break-in of the catalytic converter. Technician will need to use a Tech2 to check the verify engine run time on the Engine Hour Meter in the Instrument Panel Cluster Data Display/Data 1 List in the scan tool match. If the engine run time is less tha
full bulletin at NHTSA ↗2015 GMC Sierra powertrain problems
moderate 98 complaints filed with NHTSA · avg repair $2,500 · see powertrain across all vehicles →
Failure mileage
Complaints
98
Recalls
0
Avg fix
$2,500
2crashes
1injury
What stands out
Owners have filed 98 powertrain complaints with NHTSA against this vehicle, but no formal recall covers the issue — the federal record reflects what manufacturers have admitted, not everything owners are reporting.
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 technical bulletin provides a procedure to reprogram the transmission control module to correct a firm garage shift, start up clunk, and DTC P16F3 condition
full bulletin at NHTSA ↗This technical bulletin provides a procedure on replacing the stator shaft support for vehicles with the condition of a delayed engagement after sitting with the engine off.
full bulletin at NHTSA ↗This Preliminary Information communication provides information to the technician of an engine power reduced message on the driver information center after performing the Canada Onstar® 4G upgrade. If the concern is present park the vehicle outside and call General Motors Technical Assistance Center.
full bulletin at NHTSA ↗This preliminary informational bulletin provides diagnostic tips for a customer concern of illuminated MIL or technicians finding DTC P2818: Transmission Control Solenoid Valve'8 Stuck On.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
Owners report a broad pattern of transmission failures and engine defects in the 2015 GMC Sierra that create safety hazards and high repair costs. Transmission problems dominate the complaints: jerky or hard shifts between gears, especially from 1st to 2nd or during acceleration; sudden loss of power or inability to accelerate despite engine RPM rising; transmission slipping out of gear or into neutral without warning; and inability to shift into reverse. Several owners describe complete transmission failure while driving at highway speeds or climbing hills, forcing them off the road and creating danger from trailing traffic. Check engine codes P0700 (transmission control module) and P0711 (transmission temperature sensor) appear in multiple narratives. Owners report being told by dealers that hard shifts are "normal operation," then facing $4,000–$6,500 transmission replacement bills after warranty expiration. Torque converter failure is cited frequently, with symptoms of shuddering, violent shifting, and loss of power under load.
Engine failures are the second major issue. Owners report AFM (Active Fuel Management) lifter failure leading to camshaft damage and complete engine seizure without warning lights—often around 100,000+ miles. One owner paid $13,000 out of pocket for engine replacement; others cite $7,000+ repair estimates. Broken valve springs, bent pushrods, and low cylinder compression appear in several complaints. Owners note GM issued recalls for earlier model years (2004–2014) but their 2015 vehicles fall outside coverage.
Transmission vibration and shuddering at highway speeds (70–80 mph) recur across multiple complaints, with one owner reporting seven shop visits and nine tire replacements without resolution. Oil cooling line leaks and brake system issues also surface. Throughout, owners express frustration that dealers dismiss serious symptoms as "normal" or cannot replicate failures, while independent mechanics and transmission shops report seeing the same defects repeatedly.
Same GMC Sierra powertrain reports on nearby years: 2014 · 2016 · 2017 · 2018
Failure modes owners describe
Transmission hard shifting and jerking
Transmission shifts abruptly and harshly between gears, particularly 1st to 2nd, 2nd to 3rd, or when shifting from park to drive/reverse. Entire vehicle shakes or lurches when shift occurs.
When: Typically between 30,000 and 150,000 miles; some complaints from 4 months to 3+ years of ownership
Symptoms owners cite: Hard or harsh shifts between gears; Jerking or lurching sensation during acceleration or deceleration; Entire vehicle shaking when shifting; Difficulty shifting into reverse or drive; Delayed engagement when shifting from park
Repairs/costs cited: Dealers performed transmission fluid flushes, TCM reprogramming, and transmission harness replacement. Some complaints note $4,400–$6,500 transmission replacement costs.
Recalls/TSBs owners mention: Dealers initially claimed hard shifts were 'normal operation.' Some 2016 model year vehicles covered under special coverage program for transmission harness (P0711 code). No recall issued; some owners report transmission reprogramming or fluid service as temporary fix.
Transmission power loss and slipping
Transmission loses power or slips out of gear without warning during normal driving. Engine RPMs rise but vehicle fails to accelerate or maintains only 10–20 mph maximum speed. Vehicle may slip into neutral unexpectedly.
When: Varied: as early as 1,800 miles (new vehicle) to 147,000 miles; incidents reported within 10 months of purchase
Symptoms owners cite: Sudden loss of power while accelerating; RPMs increase but vehicle does not accelerate; Transmission slips out of gear or into neutral; Vehicle limited to 10–35 mph max speed; Engine RPM hunting/seeking proper gear; Transmission fails to engage when shifted to drive or reverse
Repairs/costs cited: Transmission replacement $4,400–$6,500+. One transmission shop reported replacing/rebuilding similar units approximately three times per week. Some repairs involved torque converter replacement.
Recalls/TSBs owners mention: GM dealers diagnosed torque converter issues and performed transmission replacements under warranty when applicable. No recall; one narrative mentions special coverage program. Multiple owners report dealer claims that symptoms are 'normal.'
Transmission failure with safety risk during highway driving
Transmission completely fails while driving at highway speeds or climbing hills, leaving vehicle without power and no engine braking. Creates imminent safety risk from oncoming/trailing traffic.
When: Various mileages; one owner ~35 mph during hill climb; another ~75 mph on highway
Symptoms owners cite: Sudden complete transmission failure mid-drive; Loss of engine braking while descending; Vehicle coasts uncontrolled on incline; No downshift response available; Loss of all power transmission engagement
Repairs/costs cited: Owners required tow service and transmission replacement ($4,400–$6,500+). One owner paid over $13k for subsequent engine replacement.
Recalls/TSBs owners mention: No manufacturer response documented in these narratives. One owner requested official recall investigation citing near-fatal accident.
Torque converter shuddering and failure
Torque converter shudders or vibrates during acceleration or shifting; vehicle feels like being struck from behind or shakes violently. Converter may fail completely, causing loss of power.
When: 100,000–140,000+ miles; one complaint at 1,800 miles
Symptoms owners cite: Shuddering or vibration during acceleration; Violent shaking when shifting; Vehicle jerks forward violently without warning; Sluggish acceleration at startup or low speed; Loss of power under load (towing); Squeaking sound from drivetrain
Repairs/costs cited: Torque converter replacement or flush and transmission filter replacement. One owner reports flushing did not resolve; failure worsened. Cost ~$400–$1,000+ parts and labor per narrative context.
Recalls/TSBs owners mention: One dealer replaced torque converter under warranty after owner had to shift manually. GM claims shuddering is 'normal operation.' No recall; some narratives reference informal service bulletins.
Transmission vibration and shuddering at highway speeds
Vehicle vibrates or shudders intensely between 40–80 mph, particularly at sustained highway speeds. Seat wobbles or shakes; passenger uncomfortable; feels unsafe.
When: Throughout ownership; some complaints within first year; one at 250 miles
Symptoms owners cite: Vibration or shuddering at 40–80 mph; Passenger seat shaking or wiggling; Vehicle feels unstable; Transmission hunts between gears; Downshifting unexpectedly when encountering headwind or hill; Feels like 6-speed instead of 8-speed transmission
Repairs/costs cited: Dealers replaced struts, ball joints, changed gear ratios, adjusted rear end, and performed transmission reprogramming. One owner had seven shop visits and nine tire replacements without resolution.
Recalls/TSBs owners mention: GM issued Bulletin #PI1354C related to vibration. Dealers claim issues are 'normal' or within specs. One dealer blamed suspension components; repairs did not resolve transmission issues.
AFM lifter failure and camshaft damage
Active Fuel Management (AFM) system lifters fail, destroying camshaft lobes and potentially leading to catastrophic engine failure. Low compression in affected cylinders; metal debris in oil.
When: 52,000–137,000 miles; one failure at ~116,000 miles
Symptoms owners cite: Check engine light illumination; Engine sputtering or rough running; Stalling or loss of power; Low cylinder compression; Abnormal noise from engine; Sudden engine shutdown without warning lights
Codes mentioned: AFM system codes, Low compression codes
Repairs/costs cited: Valve spring replacement, lifter replacement, or full engine replacement $6,000–$13,000+. One owner paid $13k out of pocket at ~116,000 miles.
Recalls/TSBs owners mention: GM issued recalls for 2004–2014 model years with AFM/DFM systems. 2015 vehicles fall outside coverage window. Service bulletins exist per owner research. GM aware of issue since 2007 per one narrative.
Transmission control module and sensor wiring harness failure
Internal wiring harness in transmission assembly fails, causing transmission control module errors and temperature sensor faults. Leads to transmission dysfunction and inability to shift properly.
When: 30,000–75,000+ miles
Symptoms owners cite: Check engine light with transmission codes; Transmission rough/erratic shifting; Transmission hunting for correct gear; Multiple scan codes related to TCM and temperature sensor
Repairs/costs cited: Internal wiring harness replacement required. One narrative mentions 2016 model year covered under special coverage program; 2015 may not be included.
Recalls/TSBs owners mention: One owner reported VIN included in special coverage program. Multiple 2015 owners note they fall outside applicable coverage, despite identical part numbers to covered 2016 vehicles.
Valve spring breakage and engine damage
Valve springs break spontaneously during normal driving, destroying pistons, cylinder head, and potentially cracking engine block. Not related to abuse or improper maintenance.
When: ~137,000 miles and ~116,000 miles
Symptoms owners cite: Engine running rough after valve spring breaks; Engine suddenly shuts down; No warning before failure; Piston and head damage upon inspection; Cracked engine block
Repairs/costs cited: Engine teardown and inspection required; full engine replacement likely necessary. Owner noted 'regular service and taken good care of truck.'
Recalls/TSBs owners mention: No manufacturer response documented. Failures occurred on well-maintained vehicles.
Transmission inability to hold park; rollback
Vehicle rolls backward while in park without operator input, or transmission fails to remain in selected gear (park, neutral, or drive). Gear shifter stuck or unable to select intended gear.
When: Various; one at 8,000 miles
Symptoms owners cite: Vehicle coasts backward out of park; Gear shifter stuck or unresponsive; Transmission does not hold selected gear; Shifter moves unintentionally after being set
Repairs/costs cited: Shifter cable replacement; transmission may require repair or overhaul. One case required manual intervention under vehicle to move shifter cable.
Recalls/TSBs owners mention: One narrative notes employee thought vehicle was in park when it was in neutral; distinction between park and neutral failure unclear in some complaints.
Engine failure and seizure without warning
Engine seizes or shuts down completely while driving at highway speed without any preceding warning lights or diagnostic codes. Often attributed to lifter or internal damage.
When: ~107,000–116,000 miles
Symptoms owners cite: Sudden complete engine shutdown; No warning lights or gauges before failure; Loss of power while ascending hill or at highway speed; Engine will not restart
Repairs/costs cited: Full engine replacement required. One owner paid $13,000+ out of pocket.
Recalls/TSBs owners mention: No recall or assistance offered. Dealership service department looked at vehicle but did not investigate root cause.
Synthesized from 98 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 1 most recent
I've been having transmission issues which cause harder shifting than usual. upon research, I found that the 2016 GMC Sierra's have a special coverage that replaced the transmission harness which throws the code P0711 for the temperature sensor and P0700 which is the generic transmission code. The only difference between my VIN and the VINs covered under this special coverage is that my Sierra is…
Had powertrain trouble with your 2015 GMC Sierra?
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 GMC Sierra?
It's a documented issue but not catastrophic. 98 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?
Across the 50 complaints that reported odometer mileage, most powertrain failures cluster between 9,000 and 92,000 miles, with the median around 42,000. A quarter of owners report trouble before 9,000; a quarter make it past 92,000. 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/GMC/Sierra.
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.