Introduction
Unleash the full potential of your 6.6L Duramax with the GM Duramax LMM Downpipe-Back Exhaust System, built for 2007.5–2010 Chevrolet Silverado and GMC Sierra 2500/3500HD models. Available in both 4-inch and 5-inch diameters, this system maximizes exhaust flow, reduces EGTs and delivers a deep, aggressive tone for serious off-road performance.
Vehicle Compatibility
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Years: 2007.5-2010
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Makes: Chevrolet Silverado, GMC Sierra
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Models: 2500HD, 3500HD
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Engine: 6.6L Duramax LMM (diesel)
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Body: Pickup
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Cab Styles: Extra Cab (EC), Crew Cab (CC)
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Box Lengths: Short Box (SB), Long Box (LB)
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Configuration: Single Rear Wheel (SRW) and Dually (DRW)
Please Note: Not compatible with Cab & Chassis or 3-bolt flange models
Technical Specifications
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Material: 16-gauge T409 stainless steel
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Diameter: 4” or 5” mandrel-bent tubing
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Configuration: Downpipe-back, single outlet
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Clamps: Stainless steel band clamps
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Finish: Natural brushed stainless
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Use: Off-road and race applications only
Features
- Performance downpipe-back design for maximum flow
- Offered in 4' and 5' T409 stainless steel for strength and longevity
- 16-gauge stainless construction resists corrosion and fatigue
- Contour Bent Hangers ensure precise, rattle-free alignment
- Stainless steel clamps provide leak-free joints
- Prewelded flanges and contour bends simplify installation
- No bungs for a clean, unrestricted design
- Fits Cab/Box configurations: EC-CC/SB-LB-Dually
- Ease of installation with all hardware included
- Optional muffler add-on available for quieter operation
Benefits
- Frees up exhaust flow for noticeable performance gains
- Lowers EGTs under heavy load and towing
- Reduces backpressure, improving throttle response
- Durable T409 stainless withstands high-heat, high-vibration use
- Straightforward bolt-on setup for minimal downtime
- Delivers a powerful, deep exhaust tone ideal for off-road builds
Installation & Notes
- Bolt-on design—no welding or cutting required
- Uses Contour Bent Hangers for factory-style alignment
- Professional installation recommended for fit and clearance
- Must be paired with proper race tuning to function correctly
- For competition/off-road use only
Frequently Asked Questions
Is this exhaust street-legal?
No. It is for off-road or race use only and not legal on public highways.
What’s the difference between 4” and 5” Duramax LMM exhaust?
The 4” provides excellent fitment and moderate tone; the 5” offers deeper sound and maximum flow.
Does Duramax LMM exhaust include all necessary hardware?
Yes. Includes clamps, Contour Bent Hangers and all mounting hardware.
Do I need tuning after installation?
Yes. Proper race tuning is required for the system to function correctly.
Will Duramax LMM Exhaust System lower EGTs?
Yes. The free-flowing design reduces backpressure and lowers exhaust gas temperatures for better off-road performance.
Shipping Policy at Tuner Depot
At Tuner Depot, we understand the importance of timely delivery for your performance parts. We're committed to
ensuring a seamless shipping experience, striving to dispatch your orders with utmost efficiency and speed.
Our Shipping Policy: Our aim is to dispatch all orders within two business days, providing you
with a quick and efficient processing time. However, unforeseen circumstances beyond our control may
occasionally impact shipping times.
Factors Affecting Shipping:
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Weather Conditions: Adverse weather conditions such as rain, snow, or sleet may affect
delivery timelines. We will make every effort to minimize any delays.
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Holiday Periods: Please note that our shipping center will be closed during holidays. We
will resume shipping promptly on the next business day. Allow for potential delays during peak seasons, but
rest assured, we will keep you informed every step of the way.
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Staff Availability: Unforeseen circumstances can occasionally affect our staffing levels,
possibly leading to minor delays. We are committed to swiftly resolving any issues to maintain our high
standards of service.
We genuinely appreciate your understanding and patience during any unexpected obstacles. Be assured that we
will utilize every resource available to deliver your performance parts promptly.
Items Eligible for Return
These items can be returned within 30 days of the purchase date, provided they are unopened, unused, and in
their original packaging:
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Tuning devices – for example, an unopened/unused Mini Maxx V1/V2 or blank EFI Live Device
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Cables and device accessories – for example, an unopened/unused switch, bypass cable, universal pyrometer
& docking station
Final Sale / Non-Refundable Items
The following items are final sale and cannot be returned:
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Custom tuning – including additional tune files purchased separately or custom tuning purchased with a
device
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Exhausts and race pipes – this also includes downpipes purchased separately from an exhaust or race pipe
- EGR kits
Manufacturer Warranty
All items we sell include a 90-day manufacturer warranty.
If an item is being returned due to a manufacturer defect, it may be returned for a full refund, exchange, or
replacement with a similar item of equal or lesser value.
For eligible items being returned for any other reason, the same options apply: full refund, exchange, or
replacement with a similar item of equal or lesser value, provided the item meets the return requirements
above.
Return Process
All returns must be approved by our team before being sent back. We will provide a valid RMA number and
prepaid return label for the return.
Please do not send any items back without an approved RMA and the return label provided by us, as returns
sent without these will not be accepted or processed.
Off-Road Use Only
These products are intended for off-road, race, and competition use only and may not be legal for use on
public highways where emissions laws apply. Check your local and state regulations before purchase.