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T304 Stainless Steel
The Purest Stainless Steel used in Exhaust System Manufacturing
High Rust Resistance
Lasts Up To 20+ years
Looks Better
T409 Stainless Steel
The Standard Stainless Steel used in Exhaust System Manufacturing
Low Rust Resistance
Lasts Up To 5-8 Years
Looks Dull
Attention
A 2022 Cummins Tune Package was added to your cart. This tune is a beta tune that may cause the following:
- Low power
- Poor fuel mileage
- Engine codes that may appear
- Poor shifting characteristics
For a tested and proven tune, please view our Ram Cummins 6.7L All-in-One DPF/DEF/EGR Delete Kit w/ECM Swap (2022-2024)
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.
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
Compatibility
- 2007.5–2010 Chevrolet Silverado 2500HD / 3500HD 6.6L Duramax LMM
- 2007.5–2010 GMC Sierra 2500HD / 3500HD 6.6L Duramax LMM
- Fits EC-CC/SB-LB-Dually configurations
- Not compatible with Cab & Chassis or 3-bolt flange models
Technical Specifications
- Material: 16-gauge T409 stainless steel
- Diameter: 4” or 5” mandrel-bent tubing
- Configuration: Downpipe-back, single outlet
- Clamps: Stainless steel band clamps
- Finish: Natural brushed stainless
- Use: Off-road and race applications only
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
Q1: Is this exhaust street-legal?
A1: No. It is for off-road or race use only and not legal on public highways.
Q2: What’s the difference between 4” and 5” Duramax LMM exhaust?
A2: The 4” provides excellent fitment and moderate tone; the 5” offers deeper sound and maximum flow.
Q3: Does Duramax LMM exhaust include all necessary hardware?
A3: Yes. Includes clamps, Contour Bent Hangers and all mounting hardware.
Q4: Do I need tuning after installation?
A4: Yes. Proper race tuning is required for the system to function correctly.
Q5: Will Duramax LMM Exhaust System lower EGTs?
A5: Yes. The free-flowing design reduces backpressure and lowers exhaust gas temperatures for better off-road performance.
Important Product Information
Off-Road Use Only: The products sold on this website are intended for off-road use only, and may not be legal for use on public highways where pollution control laws apply.
Check Local Laws: Before purchasing and installing any of these parts, please check your local and state laws to confirm whether the modifications are legal in your area.
Professional Installation Recommended: These kits and parts are strongly recommended to be installed by professional mechanics only. Improper installation may lead to performance issues or damage to your vehicle. Unless specified differently on the product page, our parts do not include installation instructions. They are intended for individuals with a proficient understanding of mechanical systems and procedures. Like many aftermarket parts compatible with a variety of vehicles, minor adjustments or modifications may be necessary during the installation process. We cannot accept returns or offer refunds on the basis of an inability to complete the installation due to the absence of instructions.
Warranty: The use of these parts will void the warranty of your vehicle. Please confirm with your vehicle manufacturer before purchase and installation.
No Liability: Tuner Depot is not responsible for any damage or issues that may arise from the use of these parts.
Product Images: Product images are for illustrative purposes only and may differ from the actual product due to manufacturer design changes or improvements.
Returns & Refunds: All sales of exhaust pipes, straight pipes, and engine pipes are final and Non-Returnable and Non-Refundable.
No Performance Guarantees: While these parts are designed to enhance the performance of your vehicle, no guarantees are made regarding the specific performance gains that will be achieved.
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.
- Weather Conditions: Adverse weather conditions such as rain, snow, or sleet may affect delivery timelines. We will make every effort to minimize any delays.
- 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.
- 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.
- Choosing a selection results in a full page refresh.
US Customers - Due to the US Government shutdown, US deliveries may delayed between 1-3 weeks. Thank you for your patience









