Buick · Known Issues

2015 Buick Regal Problems: 4 Issues Every Owner Should Know

2015 model year · NHTSA recalls, manufacturer TSBs, and owner forum reports · Updated June 2026

According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 2015 Buick Regal has 4 documented known issues, with 2 rated critical. The most serious are Regal Aisin AF40 6-Speed Harsh Shifts / Shudder ($150-$5,500 repair) and Regal 2.0L Turbo (LHU/LTG) Timing Chain Stretch ($1,800-$3,500 repair). Across all issues, repair costs range from $150 to $5,500. DIY maintenance guides at au7o.io.

All 4 Known Issues

On the 2011-2017 Buick Regal, the Aisin AF40 6-speed automatic in 2011-2017 Regal (and 2010-2017 LaCrosse 4-cyl, 2008-2017 Opel Insignia A) develops harsh 1-2 and 2-3 shifts, torque-converter shudder at light throttle, and delayed engagement, usually 80,000-150,000 miles. GM's "lifetime fill" claim is widely disputed by independent shops.

This issue also affects: Buick Enclave, Buick Encore GX, Cadillac Escalade

Common Symptoms

harsh shifts
torque converter shudder
delayed engagement
flare on upshift

How to Fix

Drain-and-fill ATF every 50,000 miles using AC Delco / Aisin AFW+ (or JWS3309 equivalent) — about $150-$250 DIY (5-6 qt drained per service). Severe shudder may need torque converter or valve body work ($1,500-$3,500). If neglected past 120k miles, full rebuild may be required ($3,500-$5,500).

Typical repair cost:$150 - $5,500

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Manually Verified

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On the 2011-2017 Buick Regal, regals equipped with the GM 6T40/6T70 six-speed automatic can develop torque-converter shudder, slipping or flare on the 2-6 shift, and harsh/delayed shifts. The 6T40 issue is commonly debris blocking the 2-6 clutch regulator valve circuit; the 6T70 suffers wear in the accumulator/solenoid valve bores and torque-converter clutch shudder, sometimes worsened by overheated, degraded fluid.

Common Symptoms

Shudder/vibration under light acceleration
Slipping or RPM flare between gears
Hard or delayed shifts
Surge when shifting into/out of 2nd or 6th

How to Fix

Start with a full transmission fluid/filter service (fixes many shudder cases). Persistent problems require valve body cleaning/rebuild, accumulator bore repair, or torque converter replacement. Use only the correct GM spec fluid.

Typical repair cost:$300 - $2,500

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On the 2011-2017 Buick Regal, the 2.0L Turbo LHU (2011-2014) and LTG (2014+) in Regal — and shared LaCrosse, Cadillac ATS/CTS — develops timing chain stretch around 80,000-130,000 miles. Symptoms: cold-start rattle, P0008/P0017 codes, eventual loss of cam timing. Aggravated by extended oil intervals and stop-start fleet use.

This issue also affects: Buick Cascada, Buick Enclave, Buick Encore

Common Symptoms

cold start rattle
misfire
check engine light
reduced power

How to Fix

Full timing chain kit including chain, tensioner, guides, sprockets — $1,800-$3,000 at independent. Stick to 5,000-7,500 mile oil intervals with dexos1 full-synthetic 5W-30. Carbon-clean intake valves at the same service ($300-$500) since LHU/LTG are direct-injection.

Typical repair cost:$1,800 - $3,500

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On the 2011-2017 Buick Regal, like other GM direct-injected engines, the Regal's 2.0T and 2.4L DI engines accumulate carbon deposits on the back of the intake valves because fuel no longer washes the valves clean. Over tens of thousands of miles this causes cold-start misfires, rough idle, hesitation, and reduced power and economy. It is a well-documented owner complaint on the turbo cars in particular.

This issue also affects: Buick LeSabre, Buick Park Avenue, Buick Cascada

Common Symptoms

Cold-start misfire / stumble
Rough idle
Hesitation on acceleration
Reduced power and fuel economy
Misfire codes

How to Fix

Perform a walnut-blasting / manual intake valve cleaning (or chemical induction service in milder cases). Updated engine-management software and periodic intake cleaning help slow recurrence; catch-can installation reduces future buildup.

Typical repair cost:$400 - $900

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Frequently Asked Questions

What are the most common Buick Regal problems?

According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 2015-2015 Buick Regal has 4 documented issues. The most frequently reported are: Regal Aisin AF40 6-Speed Harsh Shifts / Shudder, Regal 2.0L Turbo (LHU/LTG) Timing Chain Stretch, Carbon Buildup on Intake Valves (Direct Injection). Of these, 2 are rated critical and should be addressed promptly.

Is the Buick Regal reliable?

The 2015-2015 Buick Regal has 4 known issues compiled from NHTSA recalls, manufacturer TSBs, and owner forum reports. 2 issues are rated critical: Regal Aisin AF40 6-Speed Harsh Shifts / Shudder and Regal 2.0L Turbo (LHU/LTG) Timing Chain Stretch. Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.

How much does it cost to fix common Buick Regal problems?

Repair costs for known Buick Regal issues range from $150 to $5,500, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, Regal Aisin AF40 6-Speed Harsh Shifts / Shudder, typically costs $150-$5,500 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.

What is the 2011-2017 Buick Regal Regal Aisin AF40 6-Speed Harsh Shifts / Shudder?

The Aisin AF40 6-speed automatic in 2011-2017 Regal (and 2010-2017 LaCrosse 4-cyl, 2008-2017 Opel Insignia A) develops harsh 1-2 and 2-3 shifts, torque-converter shudder at light throttle, and delayed engagement, usually 80,000-150,000 miles. GM's "lifetime fill" claim is widely… Repairs typically run $150-$5,500. Severity: high.

What is the 2011-2017 Buick Regal Regal 2.0L Turbo (LHU/LTG) Timing Chain Stretch?

The 2.0L Turbo LHU (2011-2014) and LTG (2014+) in Regal — and shared LaCrosse, Cadillac ATS/CTS — develops timing chain stretch around 80,000-130,000 miles. Symptoms: cold-start rattle, P0008/P0017 codes, eventual loss of cam timing. Aggravated by extended oil intervals and stop-… Repairs typically run $1,800-$3,500. Severity: high.

What is the 2011-2017 Buick Regal Carbon Buildup on Intake Valves (Direct Injection)?

Like other GM direct-injected engines, the Regal's 2.0T and 2.4L DI engines accumulate carbon deposits on the back of the intake valves because fuel no longer washes the valves clean. Over tens of thousands of miles this causes cold-start misfires, rough idle, hesitation, and red… Repairs typically run $400-$900. Severity: medium.

What is the 2011-2017 Buick Regal 6T70/6T40 Automatic Transmission Shudder, Slipping & Hard Shifts?

Regals equipped with the GM 6T40/6T70 six-speed automatic can develop torque-converter shudder, slipping or flare on the 2-6 shift, and harsh/delayed shifts. The 6T40 issue is commonly debris blocking the 2-6 clutch regulator valve circuit; the 6T70 suffers wear in the accumulato… Repairs typically run $300-$2,500. Severity: medium.

2015 Buick Regal Problems: 4 Issues Every Owner Should Know

All 4 Known Issues

2011-2017 Buick Regal: Regal Aisin AF40 6-Speed Harsh Shifts / Shudder#

Common Symptoms

How to Fix

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2011-2017 Buick Regal: 6T70/6T40 Automatic Transmission Shudder, Slipping & Hard Shifts#

Common Symptoms

How to Fix

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2011-2017 Buick Regal: Regal 2.0L Turbo (LHU/LTG) Timing Chain Stretch#

Common Symptoms

How to Fix

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2011-2017 Buick Regal: Carbon Buildup on Intake Valves (Direct Injection)#

Common Symptoms

How to Fix

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Other Buick Models

Frequently Asked Questions

What are the most common Buick Regal problems?

Is the Buick Regal reliable?

How much does it cost to fix common Buick Regal problems?

What is the 2011-2017 Buick Regal Regal Aisin AF40 6-Speed Harsh Shifts / Shudder?

What is the 2011-2017 Buick Regal Regal 2.0L Turbo (LHU/LTG) Timing Chain Stretch?

What is the 2011-2017 Buick Regal Carbon Buildup on Intake Valves (Direct Injection)?

What is the 2011-2017 Buick Regal 6T70/6T40 Automatic Transmission Shudder, Slipping & Hard Shifts?