GM Truck Repairs in Granby, CT
Own a Chevrolet, GMC, Cadillac, or Buick truck or SUV and dealing with a ticking noise, misfires, or transmission shudder?
At College Highway Auto, we diagnose and repair the two most common GM truck issues: AFM or DFM lifter failures and torque converter shudder problems.
We focus on real diagnostics, clear communication, and repair options that last.
GM Truck Diagnostics
AFM and DFM Lifter Repair
Torque Converter Upgrades
Granby, CT
Problem 1: AFM and DFM Lifter Collapse (Ticking and Misfires)
Many GM V8 trucks (especially 5.3L and 6.2L platforms) use Active Fuel Management (AFM) or Dynamic Fuel Management (DFM).
Over time, a lifter can fail or collapse. This often shows up as a ticking noise, a rough idle, and misfire codes.
If ignored, it can lead to camshaft damage and a much bigger repair.
Common symptoms
- Ticking noise from the top end (often most noticeable at idle)
- Misfire or shaking at idle or under load
- Check engine light with misfire codes (often random misfire)
- Loss of power, poor fuel economy, or an uneven loping idle
- Intermittent issues that come and go, especially early on
How we handle it
- Verify the concern with a road test and scan data
- Confirm misfire pattern and locate the valve train noise source
- Inspect for lifter and cam wear before it spreads metal through the engine
- Recommend the most cost effective repair path based on what we find
- Explain everything clearly before any major work begins
Tip: A light tick plus an early misfire is the time to act. Catching it early can prevent cam damage and reduce repair cost.
Problem 2: Torque converter shudder and transmission driveability issues
GM trucks are known for torque converter clutch shudder and related driveability issues in certain automatic transmissions.
Many owners describe it as a shudder, vibration, or rumble strip feeling at steady speeds or light throttle.
In some cases, the issue can progress and create excess heat and wear inside the transmission.
Common symptoms
- Shudder or vibration at cruising speeds or light throttle
- Feels like driving over rumble strips
- Surging RPM, inconsistent lockup, or harsh and odd shifting
- Fluid discoloration or overheating symptoms over time
- Problem returns after a temporary band aid fix
Our fix: upgraded torque converters
- Diagnose the root cause and confirm it is converter or TCC related
- When replacement is needed, install upgraded torque converters designed to address common converter clutch failures
- Verify proper operation after repair with road testing and scan data
- Focus on long term reliability and fewer repeat comebacks
Important: Upgraded converters are designed to address known weak points and greatly reduce repeat shudder issues compared to standard replacements.
We choose parts and repair methods aimed at long term reliability.
GM trucks we commonly see
We regularly service GM platforms including Silverado, Sierra, Tahoe, Suburban, Yukon, Escalade, and more.
If you are in Granby, CT or nearby towns and your truck has a tick, misfire, or shudder, get it checked before it turns into a larger repair.
Chevrolet
- Silverado 1500, 2500, 3500
- Tahoe and Suburban
- Colorado
GMC
- Sierra 1500 and HD
- Yukon and Yukon XL
- Canyon
GM repair FAQs
Is a ticking noise always an AFM or DFM lifter problem?
Not always. Some engines have normal injector noise, and an exhaust leak can sound like a tick.
We diagnose the source so you are not guessing and so you avoid replacing parts you do not need.
My truck shudders. Does that automatically mean I need a transmission?
Not necessarily. Many times the issue is torque converter clutch behavior.
If handled correctly, it can prevent additional transmission damage.
Can I keep driving with a misfire or shudder?
We recommend having it checked soon. Lifter and cam damage can worsen quickly, and converter shudder can increase heat and internal wear.
Early diagnosis is usually the least expensive path.