This preliminary informational (PI) bulletin provides information to dealership personnel that may be helpful when addressing underbody component corrosion with customers.
full bulletin at NHTSA ↗2018 Cadillac CT6 powertrain problems
moderate 3 complaints filed with NHTSA · avg repair $2,500 · see powertrain across all vehicles →
Complaints
3
Recalls
0
Avg fix
$2,500
When does it fail?
Of the 3 powertrain complaints filed for the 2018 Cadillac CT6, 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 5 model years of Cadillac CT6 we track for powertrain problems, this one has the fewest owner complaints on file (3).
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 Preliminary information communicates Diagnostic aids for a no start or DTC'S following a transmission replacement
full bulletin at NHTSA ↗This Preliminary information communicates Diagnostic aids for a no start or DTC'S following a transmission replacement
full bulletin at NHTSA ↗This service bulletin provides information on Transmission Adaptive Functions and Correcting Low Mileage Harsh Shifts, Slips, or Flares.
full bulletin at NHTSA ↗This bulletin provides information on identifying Non-GM Engine Calibrations for Gasoline Engines using the Tech 2 or GDS 2.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
What owners are reporting 3 most recent
Front differential case ripped in half and separated from the ring gear. The broken chunk of differential case and pinion was still attached to the driveshaft while coming to an abrupt stop. Damage done within driveshaft tunnel. No warning, no vibration, no cause for concern, just catastrophic failure. Differential and propeller shaft were replaced by an independent mechanic. Cadillac has not…
Loss of all vehicle power while traveling on the freeway at highway speeds. Vehicle check engine, power limited, and electric motor overheat warning lights come on. The combustion engine will not start, and battery power availability goes to zero. This is very dangerous to public health and safety due to instantaneous loss of combustion engine and electric battery power while in fast-moving…
My Cadillac ct6 (2018) quit working while on the expressway. I was in the middle of no where, in georgia. This made for a very dangerous situation as the car suddenly lost all power going to the wheels while driving at approx. 75 MPH. I was barely able to get around traffic to be able to pull over as there was 0 power. When the tow truck from Cadillac arrived we were told we were not allowed to…
Had powertrain trouble with your 2018 Cadillac CT6?
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 2018 Cadillac CT6?
It's a documented issue but not catastrophic. 3 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?
Based on the 3 complaints filed, powertrain issues most often appear around 26,250 miles. Some report problems earlier; some make it well past 150,000 with no symptoms. Maintenance habits matter — vehicles that received timely fluid services and were not regularly overworked tend to last longer.
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/2018/Cadillac/CT6.
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.