What ia a Valve Lifter Oil Manifold?
The DoD system uses an electro-hydraulic actuator device called the valve lifter oil manifold (VLOM) assembly. 

The VLOM is bolted to the top of the engine valley, below the intake manifold assembly.
The VLOM consists of 4 electrically operated Normally Closed Solenoids. 

Each solenoid controls the application of engine oil pressure to the intake and exhaust valve lifters on the cylinders selected to deactivate. 

Engine oil pressure is routed to the VLOM assembly from a passage on the rear of the cylinder block.

12571609 Valve Lifter Oil Manifold Compatible with Cadillac Escalade Chevy Avalanche Express Silverado Suburban Tahoe Trailblazer GMC Envoy Savana Sierra Yukon Replacement# 917-162

Part Number
    12571609
    12580901
    917-162
    917162

Fitments
    2005-2007 BUICK RAINIER 5.3L 5328CC 325CID V8 OHV, (16 VALVE)
    2007-2013 CHEVROLET AVALANCHE 5.3L 5328CC 325CID V8 FLEX OHV, (16 VALVE)
    2007-2009 CHEVROLET AVALANCHE 5.3L 5328CC 325CID V8 OHV, (16 VALVE)
    2007 CHEVROLET SILVERADO 1500 CLASSIC 5.3L 5328CC 325CID V8 ELECTRIC/GAS OHV, (16 VALVE)
    2007 CHEVROLET SILVERADO 1500 CLASSIC 5.3L 5328CC 325CID V8 FLEX OHV, (16 VALVE)
    2007 CHEVROLET SILVERADO 1500 CLASSIC 5.3L 5328CC 325CID V8 OHV, (16 VALVE)
    2007-2013 CHEVROLET SILVERADO 1500 5.3L 5328CC 325CID V8 FLEX OHV, (16 VALVE)
    2007-2009 CHEVROLET SILVERADO 1500 5.3L 5328CC 325CID V8 OHV, (16 VALVE)
    2007-2014 CHEVROLET SUBURBAN 1500 5.3L 5328CC 325CID V8 FLEX OHV, (16 VALVE)
    2007-2013 CHEVROLET SUBURBAN 1500 5.3L 5328CC 325CID V8 OHV, (16 VALVE)
    2014 CHEVROLET SUBURBAN 5.3L 5328CC 325CID V8 OHV, (16 VALVE)
    2007-2014 CHEVROLET TAHOE 5.3L 5328CC 325CID V8 FLEX OHV, (16 VALVE)
    2007-2014 CHEVROLET TAHOE 5.3L 5328CC 325CID V8 OHV, (16 VALVE)
    2005-2006 CHEVROLET TRAILBLAZER EXT 5.3L 5328CC 325CID V8 OHV, (16 VALVE)
    2006-2008 CHEVROLET TRAILBLAZER 5.3L 5328CC 325CID V8 OHV, (16 VALVE)
    2005-2006 GMC ENVOY XL 5.3L 5328CC 325CID V8 OHV, (16 VALVE)
    2005 GMC ENVOY XUV 5.3L 5328CC 325CID V8 OHV, (16 VALVE)
    2005-2009 GMC ENVOY 5.3L 5328CC 325CID V8 OHV, (16 VALVE)
    2007 GMC SIERRA 1500 CLASSIC 5.3L 5328CC 325CID V8 ELECTRIC/GAS OHV, (16 VALVE)
    2007 GMC SIERRA 1500 CLASSIC 5.3L 5328CC 325CID V8 FLEX OHV, (16 VALVE)
    2007 GMC SIERRA 1500 CLASSIC 5.3L 5328CC 325CID V8 OHV, (16 VALVE)
    2007-2013 GMC SIERRA 1500 5.3L 5328CC 325CID V8 FLEX OHV, (16 VALVE)
    2007-2009 GMC SIERRA 1500 5.3L 5328CC 325CID V8 OHV, (16 VALVE)
    2010-2013 GMC SIERRA 5.3L 5328CC 325CID V8 OHV (16 VALVE)
    2007-2014 GMC YUKON XL 1500 5.3L 5328CC 325CID V8 FLEX OHV, (16 VALVE)
    2007-2009 GMC YUKON XL 1500 5.3L 5328CC 325CID V8 OHV, (16 VALVE)
    2008-2014 GMC YUKON 5.3L 5328CC 325CID V8 FLEX OHV, (16 VALVE)
    2008-2010 GMC YUKON 5.3L 5328CC 325CID V8 OHV, (16 VALVE)

Package
1x AFM Valve Lifter Oil Manifold