This Preliminary information communicates to the dealer technician that the part numbers for the internal wiring harnesses for the 8 speed RWD transmissions are not listed in the Electronic Parts Catalog. Technicians are to refer to the information provided in this document to obtain the internal wiring harness part numbers by application.
full bulletin at NHTSA ↗2017 GMC Sierra powertrain problems
moderate 134 complaints filed with NHTSA · avg repair $2,500 · see powertrain across all vehicles →
Failure mileage
Complaints
134
Recalls
0
Avg fix
$2,500
4crashes
When does it fail?
Of the 134 powertrain complaints filed for the 2017 GMC Sierra, here's the actual mileage breakdown — failures cluster heaviest at 0-25,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
What stands out
Of the 20 model years of GMC Sierra we track for powertrain problems, this one carries the most owner complaints on file — 134.
Powertrain accounts for 32% of every owner complaint on file for this vehicle — the dominant problem area across 12 categories tracked.
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.
Customer Satisfaction Program - Certain 2014-2019 model year Chevrolet Silverado and GMC Sierra vehicles equipped with a power sliding rear window (RPO A48) may have areas of high electrical resistance on the rear defroster circuit. This could be caused, in part, by mechanical stress from opening and closing the rear power window, intrusion of debris, and use of the rear defroster. Over time, this condition could generate heat that could melt the areas surrounding the circuit. In rare instances, this heat could cause a non-propagating fire, increasing the risk of property damage or injury. Dealers will replace the buss bar covers and contact cover. If the rear window or sliding glass assembl
full bulletin at NHTSA ↗This technical bulletin provides a procedure to replace the torque converter and inspect the front pump and the TEHCM for metal.
full bulletin at NHTSA ↗This Preliminary information communicates to the dealer technician that TAC recommends the utilization of the GDS2 software to aid in diagnosing automatic transmission concerns. TAC is requesting the GDS2 session logs be sent in before the dealer contacts TAC.
full bulletin at NHTSA ↗Information on Transmission Adaptive Functions and Correcting Low Mileage Harsh Shifts, Slips, or Flares.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
The 2017 GMC Sierra's powertrain is a persistent liability. The 8-speed transmission shifts violently between gears, clunking and jerking passengers backward or forward—sometimes from day one. Shuddering plagues these trucks at highway speeds and while towing light loads; torque converters wear out by 40,000 miles, requiring $900–$7,700 repairs. Dealers flushed transmissions and reprogrammed software on the same vehicle multiple times; the problems returned within weeks or months. Owners cite at least 13 GM technical service bulletins and a Service Bulletin (#20-NA-142) acknowledging the issue, yet no recall has been issued. Three owners reported transmission failures that recurred two or three times on the same vehicle before they gave up.
The AFM (Active Fuel Management) system on 5.3L and 6.2L engines triggers lifter and push-rod failures around 60,000–85,000 miles, causing violent misfires and loss of power on the highway. One owner merged at 35 mph; the lifter failed and he lost power mid-acceleration—a safety nightmare. Engine replacement is the only fix; GM offers no assistance and instead sells extended warranties.
Transmission loss of power, slipping, and control-module failures occur without warning lights and force vehicles onto highway shoulders. One owner experienced three consecutive transmission failures. Dealers routinely claimed they couldn't reproduce intermittent problems or blamed "transmission learning" and "normal operation." Several owners mentioned pending class-action suits against GM for 2016–2020 8-speed transmission defects. The trucks leak transmission fluid, downshift unexpectedly while braking, and leave owners stranded—all while GM denies accountability.
Same GMC Sierra powertrain reports on nearby years: 2014 · 2015 · 2016 · 2018 · 2019
Failure modes owners describe
8-Speed Transmission Hard Shifts and Shuddering
Transmission shifts harshly between gears, often accompanied by shuddering, jerking, or clunking sounds. Occurs at various speeds, especially during 1st-to-2nd upshifts and low-speed downshifts. Described as violent slamming or lurching. Multiple owners report the problem recurs after dealer fluid flushes or software reprogramming, with some experiencing the issue from the day of purchase.
When: Early in ownership (as early as 4,000–6,000 miles) through 130,000+ miles; often intermittent or recurring after attempted repairs
Symptoms owners cite: Hard, violent shifts between gears; Loud clunking or banging during gear changes; Shuddering or vibration during acceleration or coasting; Jerking sensation that throws occupants forward or backward; Vehicle lurches forward unexpectedly when shifting into Drive; Transmission slams when downshifting; Rough feel at low speeds and during corners
Repairs/costs cited: Dealers perform transmission fluid flushes (20-quart service with new filter), software/TCM reprogramming, torque converter replacement (~$900–$7,782 depending on repair scope), and valve body replacement. Owners report repairs often temporary; shuddering returns within weeks to months. Replacement transmission or torque converter recommended but expensive ($6,000–$7,782). Independent shops cite GM 8L transmission design defect.
Recalls/TSBs owners mention: GM has issued at least 13 TSBs and a Service Bulletin (#20-NA-142) recommending new transmission fluid blend and software updates. Some dealers acknowledge the issue; others claim 'normal operation' or blame owner maintenance. GM has offered extended warranty programs (at owner cost). No recall issued. Class-action suits filed for 2016–2020 8L transmission models.
Torque Converter Failure
Torque converter wears prematurely, causing shuddering at highway speeds (50+ mph) and loss of power. Owners report metal shavings in transmission fluid and fluid discoloration (scorched). Occurs even with light use (no towing, minimal load). Can render vehicle undrivable without warning.
When: 40,000–130,000 miles; some reports as early as 38,000 miles on 8L90 transmission with 'sealed for life' fluid
Symptoms owners cite: Shuddering or vibration at highway speeds (50+ mph); Whining noise from transmission area; Loss of power or hesitation during acceleration; Transmission fluid scorched or discolored; Metal shavings visible in transmission pan/filter; Vehicle unable to shift smoothly or loss of propulsion
Repairs/costs cited: Torque converter replacement $900–$3,000+. Fluid flush and filter change often performed first but insufficient. Owners cite faulty 'sealed for life' transmission fluid (rated for 200,000 miles but failing at 40,000). One owner switched to AMSOIL synthetic ATF and resolved shuddering. Independent shops report this is endemic to GM 8L and 8L90 transmissions.
Recalls/TSBs owners mention: GM Service Bulletin #20-NA-142 recommends fluid replacement every 5 years or 40,000 miles (contradicting 'sealed for life' marketing). No recalls. Warranty denials common if fluid change considered 'maintenance' rather than defect repair.
Transmission Loss of Power and Stalling
Vehicle loses motive power while driving (often at highway speeds 45–70 mph), stalls, or refuses to shift. Accelerator pedal depression produces engine RPM rise but no forward motion. Occurs without warning lights in some cases. Vehicle may require restart to regain propulsion.
When: 50,000–137,000 miles; can occur multiple times on same vehicle
Symptoms owners cite: Sudden loss of power while accelerating; Vehicle stalls while driving; RPM increase without acceleration; Transmission fails to shift into intended gear; Vehicle hesitates then lurches forward; Check engine light may illuminate; Transmission control module malfunction
Codes mentioned: P0700
Repairs/costs cited: Diagnosis includes transmission control module (TCM) failure, transmission seizure, and internal mechanical wear. Transmission replacement ($6,000–$7,782) or TCM replacement needed. Multiple dealers unable to diagnose or reproduce intermittent failures. One owner reported three transmission replacements required on same vehicle.
Recalls/TSBs owners mention: No manufacturer recalls. GM corporate declined coverage for out-of-warranty vehicles. Some dealers acknowledge issue but offer no remedy. Referred to extended warranty programs (at additional cost).
Transmission Slipping and Gear Engagement Delay
Transmission fails to engage gears smoothly or slips out of gear during acceleration. RPM revs without load transfer to wheels. Cold-start hesitation common; transmission 'learns driving habits' software explanation rejected by owners. Intermittent nature makes dealer reproduction difficult.
When: Early in ownership (first oil change at 6,000 miles) through 100,000+ miles
Symptoms owners cite: RPM rev without gear engagement or forward motion; Transmission slips during acceleration; Delay in shifting from Park to Drive (3–4 seconds); Cold-start hesitation or failure to move; Transmission must be toggled (Park to Drive) to re-engage; Light-load acceleration insufficient (revs but no push); Intermittent nature; hard to reproduce for dealers
Repairs/costs cited: Software/TCM reprogramming attempted but ineffective. Owners report dealer claims 'smart transmission learning period' lasts 12,000 miles, but multiple drivers defeat this theory. Valve body, clutch, piston, and transmission plates may require replacement but dealers unable to identify root cause.
Recalls/TSBs owners mention: Dealer response: 'normal operation' or 'transmission re-learning' excuse. GMC hotline offers no remedy. Dealers state issue unfixable without full transmission replacement.
AFM Lifter Failure (5.3L and 6.2L Engines)
Active Fuel Management system-equipped lifters and push rods fail prematurely, causing severe engine misfires, loss of power, and violent shaking. Failure can bend camshaft and rods if caught late. Owners report failed components are recoverable for inspection.
When: 60,000–85,000 miles with 5–8 years of normal service
Symptoms owners cite: Lifter noise or ticking under hood; Engine misfire; check engine light flashing; Loss of power pulling onto highway; Violent shaking from engine bay; RPM gauge bouncing erratically; Unable to merge safely onto highway; Vehicle barely able to stay running
Codes mentioned: P0300, P0306, P0304
Repairs/costs cited: Failed AFM lifters and push rods removed and available for manufacturer review. Engine replacement or rebuild necessary if camshaft bent. One owner reported 158 misfire events. No inexpensive repair; design change required. Dealers offer extended powertrain warranty ($1,600–$2,000) as 'solution' instead of design correction.
Recalls/TSBs owners mention: GM offers no assistance. Known issue acknowledged by dealers who see it frequently. Extended warranty programs ($1,600–$2,000) offered but do not address root design defect. No recall. TSB #20-NA-142 and #15-06-01-002M referenced by owner but not applied to their case.
Unintended Downshift Acceleration
Transmission downshifts abruptly to lower gear while vehicle is slowing or at low speeds, causing sudden engine RPM spike and unexpected vehicle lurch forward. Overrides driver brake pedal effort, pushing vehicle into intersection or toward vehicle ahead. Occurs at 5–10 mph, unpredictably.
When: Throughout vehicle life, often recurring after dealer visits
Symptoms owners cite: Sudden downshift from high to low gear while braking; Engine RPM revs above 5,000 unexpectedly; Vehicle lurches forward, overriding brake pedal; Vehicle forced into intersection against driver intent; Occurs at 5–10 mph during stop-and-go traffic; Intermittent and unpredictable; difficult for dealer to replicate; Multiple occurrences per trip in same vehicle
Repairs/costs cited: Software/TCM reprogramming and valve body inspection attempted. Transmission electronic control module replacement performed. Multiple unsuccessful repair attempts (4–6 dealer visits common).
Recalls/TSBs owners mention: GM has denied existence of defect when contacted via lemon-law attempts. Dealers claim 'unable to duplicate' or blame driver behavior. No recall despite online reports of identical failures on 8-speed vehicles. NHTSA referenced in complaints but no action taken.
Transmission Cooler Line Rubbing and Fluid Leak
Transmission cooler return hose positioned to rub against frame component, wearing hole in aluminum return line. Discovered during long towing when transmission cooler return hose positioned improperly, leading to significant transmission fluid loss. Could cause catastrophic transmission failure if not caught.
When: During towing; discovered at 50 miles remaining on 1,100-mile trip (3500 HD model)
Symptoms owners cite: Transmission fluid leak from under transmission cooler; Hole worn in aluminum cooler return line; Hose rubbing on frame component
Repairs/costs cited: Return hose line patched temporarily; requires permanent repair or hose repositioning. Dealer reports no recall and not under warranty.
Recalls/TSBs owners mention: Dealer stated no recall, not under warranty, no manufacturer assistance. Owner considers design flaw serious.
Transmission Fluid Leak (Unknown Cause)
Transmission fluid leaks, rendering vehicle undrivable. Owners add fluid temporarily but vehicle fails completely shortly after. Root cause undetermined.
When: 30,000–35,000 miles, 30–35 mph
Symptoms owners cite: Abnormal noise from transmission; Visible transmission fluid leak; Fluid reservoir empty or low; Vehicle becomes undrivable after temporary fluid addition
Repairs/costs cited: Not diagnosed or repaired; vehicle towed to residence.
Recalls/TSBs owners mention: Dealer and manufacturer not notified.
Synthesized from 134 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 13 most recent
The contact owns a 2017 GMC Sierra 1500. While the contact's husband was driving at an undisclosed speed, the accelerator pedal was depressed; however, the vehicle failed to accelerate as intended. Additionally, the RPM increased, and the drive signal flashed on and off. The vehicle was driven to the shoulder of the roadway. The vehicle was taken to an independent mechanic where it was diagnosed…
The contact owns a 2017 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle jerked and slammed into the intended gear. The check engine warning light illuminated. The contact stated that the failure had persisted, and the vehicle had failed to accelerate as intended while depressing the accelerator pedal. The contact stated that the drive was rough, and…
There is a shuttering in the transmission as the vehicle attempts to climb slight/steep grades at slow to medium speeds. Around 1500 RPM the vibration is sent throughout the whole vehicle. Having to increase acceleration to allow the truck to shift properly to overcome the lack of power has created a dangerous situation while navigating up snowy/ice hills. The vehicle also performs a…
While operating vehicle on highway, I experience a shake/shudder when at speeds of 50 MPH and higher. Vehicle was taken to dealer stated that the torque converter did shudder. Dealer changed transmission fluid and I was advised to drive for 200 miles to see if problem was corrected. Shudder still remains and now the vibration is constant at 70 MPH. I called dealer again who said that it was…
Shifting 1st to 2nd and 2nd to 1st is very hard and jolting. It hesitates and doesn't go immediately which could cause an accident.
The contact owns a 2017 GMC Sierra 1500. The contact stated that while driving at various speeds, the vehicle would hesitate and jerk upon acceleration without warning. The contact also stated that while driving at an unknown speed, the vehicle stalled with the check engine warning light illuminated on the instrument panel. The contact had taken the vehicle to a dealer and was informed that there…
The contact owns a 2017 GMC Sierra 1500. The contact stated while driving at an undisclosed speed, the accelerator pedal was depressed; however, the vehicle failed to accelerate as intended. Additionally, the contact stated that the vehicle sputtered. The vehicle was taken to an independent mechanic and diagnosed with transmission failure. The contact was informed that the transmission needed to…
The transmission needed to be replaced car would not go in reverse or foreward at all . It only has 120,000 miles on it .
The vehicle does a hard shift from 1 to 2 second and has a shudder.
My 2017 GMC Sierra 1500 Denali started shaking violently and the rpm gage began bouncing 1/4 to 1/2 inch in a very short amount of time. I ran a maintenance facility in Europe with 317 local national and 25 U.S. employees. Two of my brother-in-laws, and one of my nephews are mechanics. Two run their own auto repair facilities. All three reported having to replace torque converters on multiple…
Had powertrain trouble with your 2017 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 2017 GMC Sierra?
It's a documented issue but not catastrophic. 134 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 59 complaints that reported odometer mileage, most powertrain failures cluster between 13,300 and 69,000 miles, with the median around 37,000. A quarter of owners report trouble before 13,300; a quarter make it past 69,000. 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/2017/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.