L5P Duramax Alternators - 2017+ 6.6L

Two body styles

The L5P launched in 2017 on the K2XX platform and moved to the T1XX body in 2020, with the HD trucks updating in 2020. Both generations are listed here. Check your model year against the individual product listing, since the alternator and bracket differ across the change.

Stretch belt applications

Some later trucks use an OEM stretch belt rather than a conventional tensioner. Confirm which system your truck has before ordering, since the belt requirement differs.

Shared with the gas trucks

GM uses a common alternator across gas and diesel trucks in this era, so the L5P takes the same unit as a gas Silverado of the same year.

Why L5P owners upgrade

These are working trucks with heavy electrical demands — grid heater draw on cold starts, plus plows, upfitter equipment, inverters, winches, auxiliary lighting and audio. Modern trucks also carry far more factory electronics than older ones, leaving less headroom to begin with.

Don't skip the wiring

Dual batteries mean longer cable runs and more connections. See our Big 3 wiring upgrade guide.

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