SERVING NORTHERN COLORADO · Fort Collins · Loveland · Windsor · Timnath · Greeley Open until 5:30 PM · (970) 224-2824

Chevy & GMC repair in Fort Collins.

Silverado 1500 / 2500HD / 3500HD, Sierra 1500 / 2500HD / 3500HD, Tahoe, Yukon, Suburban, Colorado, Canyon, Camaro, Corvette, Trailblazer, Equinox, Traverse. 5.3 / 6.2 V8, 4.3 V6, 2.7 turbo, 6.6 Duramax HD.

In short: Auto Trends services every modern Chevy and GMC — Silverado, Sierra, Tahoe, Yukon, Suburban, Colorado, Canyon, Camaro, Corvette. We address the AFM (cylinder deactivation) lifter issue, oil consumption, transmission service, and the platform-specific work the dealer charges premium rates for. OEM AC Delco parts.
What we do

GM dealer software (GDS2 / Tech 2), AC Delco parts.

For Chevy / GMC service we use GM GDS2 (modern platforms) or Tech 2 (older platforms) for diagnostics, programming, and module-level work.

For repair parts, we use AC Delco where it matters — coils, water pumps, alternators, sensors, gaskets — and OE-equivalent for everything else. The aftermarket GM parts landscape has plenty of subpar options that fail prematurely.

For the AFM (cylinder deactivation) lifter failure that affects 5.3 / 6.2 V8 owners, we diagnose with a cold compression test plus listening at idle. The fix involves replacing the failed lifter and often updating the lifter set with the latest design. We do not delete AFM (federal compliance issue).

Models We Service

Every generation we know.

Silverado / Sierra 1500

5.3 / 6.2 V8, 2.7T, 3.0 Duramax. AFM, 10-speed transmission, suspension.

Silverado HD / Sierra HD

2500HD, 3500HD. Duramax 6.6, gas 6.0 / 6.6. Allison transmission, suspension.

Tahoe / Yukon / Suburban

5.3 / 6.2 V8, 3.0 Duramax. AFM, air suspension on premium trims.

Camaro / Corvette

LT1, LT4, LT5, LT6 (C8). Manual and automatic transmission, suspension.

Colorado / Canyon

Mid-size trucks. 3.6 V6, 2.8 Duramax (older), 2.7T. Suspension, transmission.

Equinox / Traverse / Trailblazer

Crossovers. 1.5T, 2.0T, 3.6 V6. Routine and major service.

Common Symptoms

Platform-specific issues we see most.

If your vehicle is doing any of these, bring it in. None of them is guaranteed to be the part you might think — that’s why we diagnose first.

FAQ

Common questions.

What’s the AFM lifter issue?

Active Fuel Management (AFM, called DFM on later platforms) deactivates 4 cylinders under light load to save fuel. The lifters that switch the cylinder valves on and off can fail, causing a tick at idle and eventually misfire codes. We replace the failed lifter and often the full set with the updated design. Cost varies but typically $1,800–$3,200 for a single bank, $3,000–$5,000 for both.

Should I ‘delete’ AFM?

No. AFM is part of the emissions calibration. Deleting it requires a tune that bypasses emissions sensors — federal compliance issue. We address AFM failures with proper repair, not delete.

Can you service the Allison transmission?

Yes — see our Duramax page. The Allison 1000 (in HD Duramax trucks) needs disciplined fluid + filter service. We do full Allison service and rebuilds case-by-case.

What about Corvette specifically?

Yes — C5 through C8. The LS / LT engines are well-understood. C7 and C8 with DCT or eight-speed transmission have specific service requirements we follow. Performance maintenance, brakes, suspension.

Are you cheaper than the dealer?

Typically 20–35% below GM dealer rates for the same work using AC Delco / OEM parts.

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