Complete in-house rebuild service for every GM Duramax turbocharger. LB7 IHI RHF5, LLY through LML Garrett VGT, and L5P BorgWarner. Full VGT vane service, actuator diagnosis, and in-house VSR balancing since 2008.
GM has used three turbocharger suppliers across the Duramax line. The LB7 runs a fixed-geometry IHI, the LLY through LML run Garrett variable geometry units, and the L5P moved to BorgWarner. Each has its own failure patterns and rebuild requirements.
The original Duramax runs a fixed-geometry IHI RHF5, the only non-VGT turbo in the Duramax line. It is a simple, robust unit whose failures almost always trace to the LB7's famous injector problem: failing injectors wash fuel into the oil, diluted oil starves the bearings, and the turbo pays the price. Every LB7 rebuild report from us includes a check on injector history. See our IHI page for more detail on the RHF5 itself.
The LLY introduced the Garrett GT3788VA variable geometry turbo to the Duramax. It also introduced the known turbo inlet mouthpiece restriction that drives high EGTs when towing. Vane sticking from soot accumulation begins with this generation. Both the vane assembly service and an honest conversation about the inlet restriction are part of every LLY rebuild here.
The LBZ and LMM continue the Garrett GT3788VA with revisions. The LBZ is widely considered the sweet spot of the pre-emissions Duramax era. The LMM added the DPF, which brought regeneration heat cycles into the turbo's life. Vane sticking remains the defining failure, and the LMM's regen cycles accelerate carbon accumulation on trucks that see short-trip duty.
The LML runs a revised Garrett VGT in the most emissions-intensive environment of the Garrett era: DPF, DEF, and more aggressive regeneration strategies. Regen events push exhaust temperatures high enough to accelerate oil coking in the center housing if the truck is shut down mid-cycle or immediately after. Vane service, bearing replacement, and actuator verification are all standard on LML rebuilds.
The L5P moved to a BorgWarner variable geometry turbo with an electronic actuator. It is a stout unit matched to the L5P's 445+ HP factory rating. Most L5P units we see have failed from oil events or hard fleet duty rather than accumulated vane carbon, though the VGT mechanism still requires full service at rebuild. Actuator diagnosis and calibration handled in-house.
Search by Garrett, IHI, BorgWarner, GM, or ACDelco part number, engine code, or year. If your number is not listed, contact us and we can identify your unit.
| Part Number | Turbo | Engine | Application | Type |
|---|---|---|---|---|
| LB7 (2001-2004) | ||||
| 8973077111 | IHI RHF5 | 6.6L LB7 | 2001-2004 Silverado / Sierra 2500HD / 3500 | IHI OEM |
| 8971884545 | IHI RHF5 | 6.6L LB7 | 2001-2004 Silverado / Sierra 2500HD / 3500 | IHI OEM |
| 97208824 | IHI RHF5 | 6.6L LB7 | 2001-2004 Silverado / Sierra (GM PN) | GM OEM |
| LLY (2004.5-2005) | ||||
| 736554-0011 | GT3788VA | 6.6L LLY | 2004.5-2005 Silverado / Sierra 2500HD / 3500 | Garrett OEM VGT |
| 759622-5002 | GT3788VA | 6.6L LLY | 2004.5-2005 Silverado / Sierra 2500HD / 3500 | Garrett OEM VGT |
| 97303761 | GT3788VA | 6.6L LLY | 2004.5-2005 Silverado / Sierra (GM PN) | GM OEM |
| LBZ / LMM (2006-2010) | ||||
| 759622-5003 | GT3788VA | 6.6L LBZ | 2006-2007 Silverado / Sierra 2500HD / 3500 | Garrett OEM VGT |
| 763333-5002 | GT3788VA | 6.6L LMM | 2007.5-2010 Silverado / Sierra 2500HD / 3500 | Garrett OEM VGT |
| 98011735 | GT3788VA | 6.6L LBZ / LMM | 2006-2010 Silverado / Sierra (GM PN) | GM OEM |
| 12641643 | GT3788VA | 6.6L LMM | 2007.5-2010 Silverado / Sierra (GM PN) | GM OEM |
| LML (2011-2016) | ||||
| 785580-5004 | Garrett VGT | 6.6L LML | 2011-2016 Silverado / Sierra 2500HD / 3500 | Garrett OEM VGT |
| 12639460 | Garrett VGT | 6.6L LML | 2011-2016 Silverado / Sierra (GM PN) | GM OEM |
| 12661032 | Garrett VGT | 6.6L LML | 2011-2016 Silverado / Sierra (GM PN) | GM OEM |
| 848212-5001S | Garrett VGT | 6.6L LML | 2011-2016 Silverado / Sierra service replacement | Garrett OEM VGT |
| L5P (2017+) | ||||
| 12707525 | BorgWarner VGT | 6.6L L5P | 2017-2019 Silverado / Sierra 2500HD / 3500 | GM OEM |
| 12704556 | BorgWarner VGT | 6.6L L5P | 2017-2019 Silverado / Sierra 2500HD / 3500 | GM OEM |
| 12712101 | BorgWarner VGT | 6.6L L5P | 2020+ Silverado / Sierra 2500HD / 3500 | GM OEM |
| Actuators / Components | ||||
| 763527-5001 | VGT Vane Assembly | 6.6L LLY-LMM | Garrett VGT unison ring and vane kit | Component |
| 12643471 | VGT Actuator / Solenoid | 6.6L LML | 2011-2016 turbo vane position solenoid | GM Component |
| 98062755 | Vane Position Sensor | 6.6L LLY-LMM | 2004.5-2010 VGT position sensor | GM Component |
| 97379588 | Turbo Oil Feed Line | 6.6L LB7-LMM | Oil supply line, replace at rebuild | GM Component |
| 12642154 | Turbo Oil Feed Line | 6.6L LML | Oil supply line, replace at rebuild | GM Component |
| 97188674 | Turbo Drain Gasket | 6.6L LB7-LML | Oil drain seal, replace at rebuild | GM Component |
| 12637691 | Turbo Mount Gasket | 6.6L LML | Exhaust side gasket, replace at install | GM Component |
| 848212-5002S | Garrett VGT | 6.6L LML | 2011-2016 alternate service number | Garrett OEM VGT |
| 17503551 | Reman VGT | 6.6L LML | 2011-2016 GM remanufactured assembly | GM Reman |
No results? Contact us at sales@theboostlab.com with your part number and we can identify your unit.
The defining LB7 failure chain. Failing injectors push fuel into the cylinders and past the rings into the crankcase. Fuel-diluted oil loses viscosity and film strength, and the turbo bearings are among the first casualties. If the injectors have not been addressed, the rebuilt turbo inherits the same contaminated oil supply. We flag this on every LB7 rebuild report.
The defining failure on LLY through LML. EGR soot and regen carbon accumulate on the vanes and unison ring until movement becomes restricted. Slow response, surging, overboost or underboost codes, and limp mode follow. Trucks that idle extensively or run short trips accumulate carbon fastest. Full vane assembly disassembly and cleaning is part of every VGT rebuild here, never just a cartridge swap.
DPF regeneration on the LMM and LML pushes exhaust temperatures far above normal operation. Shutting down during or immediately after a regen traps that heat in the turbo center housing and bakes the residual oil into carbon. Repeated cycles restrict oil passages and starve the bearings. If your truck regens, let it idle down before shutdown.
The LLY turbo inlet mouthpiece restriction forces the compressor to work harder for the same airflow, raising outlet temperatures and EGTs under load. Sustained towing in this condition shortens bearing and seal life. The restriction is a known quantity with a known fix, and we discuss it on every LLY rebuild.
These trucks work for a living, and oil that has been in service too long loses its protective qualities under diesel soot loading. Journal bearing wear from degraded oil is the baseline finding across all generations. Shorter intervals with a quality oil are the cheapest turbo insurance available.
The VGT actuator and vane position sensor fail from heat and vibration, and a failing actuator often masks or mimics stuck vanes. We diagnose the actuator and sensor as part of every VGT rebuild so you are not chasing electrical faults after installation.
Start your rebuild request in our repair system. Every Duramax job is fully documented from intake through return shipment with in-house VSR balancing.
Start Your Rebuild Request37833 Pineapple Ave Unit A • Dade City, FL 33523 • sales@theboostlab.com