Complete in-house rebuild service for every GM Duramax generation. LB7 IHI RHG6 through L5P BorgWarner VGT. VGT vane cleaning and inspection on every LLY through L5P rebuild. In-house VSR balancing since 2008.
The first-generation Duramax LB7 uses an IHI RHG6 fixed geometry turbocharger -- a larger IHI unit than the RHF5 used on light-duty applications. Oil and water cooled. No variable geometry vanes, which makes the LB7 turbo more straightforward to rebuild than every subsequent Duramax generation. The LB7 turbo itself is generally reliable when the engine oil is maintained properly. The dominant failure cause is the LB7's infamous injector problem.
The LB7 injector failure is the most important context for every LB7 turbo rebuild. The factory injectors are prone to internal cracking that allows fuel to leak into the crankcase, diluting engine oil and contaminating the turbo oil supply. Bearing failure from fuel-diluted oil is the most common LB7 turbo failure we see. If the injectors have not been addressed before the turbo rebuild, the rebuilt turbo faces the same contaminated oil from day one. We flag this on every LB7 rebuild report.
The LLY introduced the first VGT (variable geometry turbocharger) in the Duramax lineup -- the Garrett GT3788VA. The variable vane system allows the turbo to function like a small turbo at low RPM for fast spool and a large turbo at high RPM for maximum flow. This made the LLY significantly more responsive than the LB7 but also introduced the VGT vane sticking issue that would follow the Duramax lineup through several generations.
The LLY is known for overheating under sustained towing loads -- a combination of an undersized radiator and the heat load generated by the VGT-equipped engine. The turbo inlet manifold on the LLY is also restrictive, contributing to high EGTs under load. Every LLY VGT rebuild includes full vane disassembly, cleaning, and inspection.
The LBZ is widely regarded as the most desirable Duramax generation -- the last without DPF emissions equipment, with the most power of any pre-DPF Duramax, and with the updated GT3788VA that addressed several LLY cooling and turbo inlet issues. The LBZ made 360 HP and 650 lb-ft from the factory and responds well to tuning on a stock turbo.
The LBZ uses the same GT3788VA as the LLY but without the VPS adapter requirement -- the later sensor connection is standard. The same VGT vane sticking issue applies but is less common on the LBZ than the LLY due to the improved cooling system managing EGT more effectively. Every LBZ VGT rebuild includes full vane assembly cleaning and inspection.
The LMM carried the same GT3788VA turbo as the LBZ but introduced the Diesel Particulate Filter (DPF) to meet 2007.5 emissions standards. The DPF regeneration cycle burns accumulated soot from the filter by raising exhaust temperatures -- a process that puts additional thermal stress on the VGT vane assembly over time. LMM turbos that have accumulated high mileage and many regen cycles show more accelerated vane wear than comparable LBZ units.
The same 848212-5001S Garrett updated unit covers LLY, LBZ, and LMM -- making parts availability straightforward for all three generations. LMM rebuilds are handled identically to LBZ but we ask about DPF status and regen history because it directly predicts what we will find in the vane assembly at teardown.
The LML received an updated Garrett GTA3788LVA -- the "A" suffix indicating a revised CHRA with improved vane mechanism over the GT3788VA used on LLY through LMM. The LML made 397 HP and 765 lb-ft from the factory, a significant jump from the LMM. Emissions equipment expanded to include SCR (selective catalytic reduction) with DEF injection.
The LML has a well-documented Bosch CP4 high-pressure fuel pump failure mode. The CP4 pump can fail by sending metallic debris throughout the entire high-pressure fuel system -- injectors, rails, and lines. This is not a turbo issue directly, but when a CP4 failure happens it often contaminates the engine oil system, which then affects the turbo. LML rebuilds are assessed for CP4 history before quoting. GM 12642314 and 12642129 are the primary GM part numbers.
GM switched turbocharger suppliers with the L5P -- the 2017-and-newer Duramax uses a BorgWarner B2BV-70A electronically-controlled variable geometry turbocharger rather than the Garrett units used through the LML. The B2BV-70A delivers faster spool, improved exhaust braking, and supports up to 31 psi factory boost -- significantly more than earlier generations. The L5P also added a dedicated turbocharger oil supply line not present on earlier models.
GM resolved the CP4 fuel pump issue on the L5P by switching to the Denso HP4 pump, which is significantly more reliable. The L5P is also the most powerful factory Duramax -- 2024-refresh trucks make 470 HP and 975 lb-ft. The BorgWarner VGT vane mechanism on the L5P is generally robust but requires the same VGT vane inspection at rebuild as every other Duramax generation. Contact us with the model year before shipping as L5P parts vary slightly between production runs.
Search by Garrett part number, BorgWarner number, GM OEM number, or engine code. LLY, LBZ, and LMM share the 848212-5001S Garrett number -- the generation badge tells you which application applies.
| Part Number | Turbo Model | Engine | Application | Notes |
|---|---|---|---|---|
| 8973866875 | IHI RHG6 | LB7 | 2001-2004 GM 6.6L Duramax LB7 | GM OEM / IHI Fixed Geo |
| 8971371098 | IHI RHG6 | LB7 | 2001-2004 GM 6.6L Duramax LB7 | IHI OEM |
| 8971371099 | IHI RHG6 | LB7 | 2001-2004 GM 6.6L Duramax LB7 | IHI OEM |
| 97228505 | IHI RHG6 | LB7 | 2001-2004 GM 6.6L Duramax LB7 | GM OEM |
| 860218 | IHI RHG6 | LB7 | 2001-2004 GM 6.6L Duramax LB7 | GM OEM |
| 848212-5001S | Garrett GT3788VA | LLY LBZ LMM | 2004.5-2010 GM 6.6L Duramax LLY/LBZ/LMM | LLY requires 771864-0001 VPS adapter |
| 773540-5001S | Garrett GT3788VA PowerMax | LLY LBZ LMM | 2004.5-2010 GM 6.6L Duramax LLY/LBZ/LMM | Garrett PowerMax Stage 1 |
| 771864-0001 | VPS Adapter | LLY | 2004.5-2005 LLY only -- required with 848212-5001S | VPS Adapter -- LLY only |
| 8973525640 | Garrett GT3788VA | LLY | 2004.5-2005 GM 6.6L LLY | GM OEM |
| 8973525641 | Garrett GT3788VA | LLY | 2004.5-2005 GM 6.6L LLY | GM OEM |
| 8973525643 | Garrett GT3788VA | LLY | 2004.5-2005 GM 6.6L LLY | GM OEM |
| 8973525644 | Garrett GT3788VA | LLY | 2004.5-2005 GM 6.6L LLY | GM OEM |
| 8973525645 | Garrett GT3788VA | LLY | 2004.5-2005 GM 6.6L LLY | GM OEM |
| 8973525646 | Garrett GT3788VA | LLY | 2004.5-2005 GM 6.6L LLY | GM OEM |
| 8973868220 | Garrett GT3788VA | LBZ | 2006-2007 GM 6.6L LBZ | GM OEM |
| 8973868221 | Garrett GT3788VA | LBZ | 2006-2007 GM 6.6L LBZ | GM OEM |
| 8973868223 | Garrett GT3788VA | LBZ | 2006-2007 GM 6.6L LBZ | GM OEM |
| 8973868233 | Garrett GT3788VA | LBZ | 2006-2007 GM 6.6L LBZ | GM OEM |
| 8973878962 | Garrett GT3788VA | LBZ | 2006-2007 GM 6.6L LBZ | GM OEM |
| 97387896 | Garrett GT3788VA | LBZ | 2006-2007 GM 6.6L LBZ | GM OEM |
| 1845178C94 | Garrett GT3788VA | LMM | 2007.5-2010 GM 6.6L LMM | Navistar cross-ref |
| 848212-5002S | Garrett GTA3788LVA | LML | 2011-2016 GM 6.6L Duramax LML | Garrett New OEM |
| 800799-0002 | Garrett GTA3788LVA | LML | 2011-2016 GM 6.6L Duramax LML | Garrett OEM |
| 800799-0003 | Garrett GTA3788LVA | LML | 2011-2016 GM 6.6L Duramax LML | Garrett OEM |
| 886976-5004S | Garrett GTA3788LVA PowerMax | LML | 2011-2016 GM 6.6L Duramax LML | Garrett PowerMax Stage 1 600HP |
| 12642314 | Garrett GTA3788LVA | LML | 2011-2016 GM 6.6L Duramax LML | GM OEM |
| 12642129 | Garrett GTA3788LVA | LML | 2011-2016 GM 6.6L Duramax LML | GM OEM |
| 792593-0001 | VGT Solenoid | LML | LML VGT Control Valve Solenoid | Component |
| 763527-0712 | VGT Vane Position Sensor | LML | LML VGT Vane Position Sensor | Component |
| 12680639 | BorgWarner B2BV-70A | L5P | 2017-2023 GM 6.6L Duramax L5P | GM OEM BorgWarner VGT |
| 12665196 | BorgWarner B2BV-70A | L5P | 2017-2023 GM 6.6L Duramax L5P | GM OEM |
| 12699552 | BorgWarner B2BV-70A | L5P | 2017-2023 GM 6.6L Duramax L5P | GM OEM |
| 12699553 | BorgWarner B2BV-70A | L5P | 2017-2023 GM 6.6L Duramax L5P | GM OEM |
Every Duramax generation has its own dominant failure pattern tied to that generation's engine-specific issues. The turbo is almost never the root cause -- it is the last thing to break in a chain that started elsewhere.