• High Output Alternator for GMC Sierra (2014-2018) 4.3L 5.3L 6.0L 6.2L
  • High Output Alternator for GMC Sierra (2014-2018) 4.3L 5.3L 6.0L 6.2L
  • High Output Alternator for GMC Sierra (2014-2018) 4.3L 5.3L 6.0L 6.2L
  • Action Shot: GMC Sierra Driving Fast

High Output Alternator for GMC Sierra (2014-2018) 4.3L 5.3L 6.0L 6.2L

$404.95
$404.95
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High-Amp 350A Replacement Alternator for 2014-2018 GMC Sierra (K2XX)

What it Does: The 350-amp high output alternator delivers sustained electrical current to power heavy auxiliary loads, audio setups, winches, and fleet equipment on 2014-2018 GMC Sierra trucks without system voltage drop.

The Stock GMC Sierra Charging System Bottleneck

The factory 150-amp to 170-amp charging units fitted to the K2XX Sierra struggle under sustained electrical load. Factory rectifiers and internal voltage regulators suffer thermal saturation when powering high-amperage auxiliary lighting, commercial snow plows, heavy winches, or aftermarket audio systems. This excessive thermal stress leads to early diode breakdown, premature rotor failure, and critical voltage drop that impairs electronic throttle control and direct-injection management systems.

The Engineering Solution

Constructed in the USA, this heavy-duty 350-amp alternator utilizes precision copper hairpin-wound stators and a heavy-duty 12-diode bridge rectifier to maximize current output while maintaining thermal efficiency. The assembly features an upgraded rotor core and high-grade aluminum drive-end housings for improved heat dissipation over OEM units like 84206550 and 104211-8340. It maintains stable DC voltage output across all RPM ranges, supplying high amperage at idle without spiking chassis modules.

What's Included

  • 1 x 350 Amp High Output Alternator

Technical Specifications

Fitment 2014-2018 GMC Sierra 1500 / 2500HD / 3500HD
Engine / Chassis LV3 (4.3L), L83 (5.3L), L96 (6.0L), L86 (6.2L) / K2XX
Stock Output 285–420 hp / 305–460 lb-ft
Replaces OEM Part # 42074, 14007, 11785, 10255, 42093, 14009, 42095, 14020, 104211-8340, 104211-8350, 22747894, 22747896, 104211-9110, TN104211-9110, 104211-9112, 104210-6870, 1042106860, 2100521, 22065, 22069, 2100518, 2100295, 22068, 2100285, 22048, 84206550, 84143542, 84143539, 23304114, 22949466, 84143543, 84143540

Compatibility

  • 2014-2018 GMC Sierra 1500 4.3L V6
  • 2014-2018 GMC Sierra 1500 5.3L V8
  • 2014-2018 GMC Sierra 2500HD / 3500HD 6.0L V8
  • 2014-2018 GMC Sierra 1500 6.2L V8

Frequently Asked Questions & Fitment Warnings

Does this fit the K2XX Sierra?

Yes, this unit directly bolts onto the 2014-2018 GMC Sierra platform equipped with the LV3, L83, L96, or L86 engine configurations using factory bracket mounting positions.

Do I need to upgrade the primary charging cable?

Due to the substantial 350-amp output rating, upgrading to a 1/0 AWG fused battery-to-alternator cable (Big 3 upgrade) is strongly recommended to handle current throughput safely.

The GMC Professional Grade Standard

Engineered for high-demand work trucks, heavy commercial towing rigs, and off-road trail vehicles, this high-output system provides reliable voltage stability during grueling duty cycles and sub-zero winch recoveries without risk of electrical brownouts.

Fitment

Make

GMC

Engine Size
  • 4.3L
  • 5.3L
  • 6.0L
  • 6.2L

Year
  • 2014
  • 2015
  • 2016
  • 2017
  • 2018

Warranty

All products are backed by our Limited Lifetime Warranty. We stand by our quality. [See terms]
High Output Alternator for GMC Sierra (2014-2018) 4.3L 5.3L 6.0L 6.2L

$404.95