FITMENT
- 2015.5-2016 6.6L Silverado & Sierra Duramax 2500HD/3500HD LML engine models with the 3-bolt flange.
- Does NOT Fit 2011-2015.5 model with the V-Band Clamp style.
- Please physically inspect underneath your truck to verify your turbo discharge style before purchasing!
DESCRIPTION
Product Overview
- In mid-2015.5, GM updated the 6.6L Duramax LML downpipe connection to a 3-hole triangular flange. Installing an earlier LML pipe on a 2015.5–2016 model results in severe fitment issues and exhaust leaks. Additionally, running a completely open straight pipe on these late LML trucks can cause intense cabin drone during highway towing.
- The 4" LML DPF Delete Pipe is engineered specifically for late-model LML trucks. The integrated high-flow straight-through performance muffler flushes out intense backpressure and lowers towing EGTs while keeping the exhaust tone deep, refined, and completely drone-free inside the cab.
Key Features
- Premium Material: Full 4-inch mandrel-bent T409 stainless steel tubing built to resist extreme thermal stress, road salt, and harsh winter corrosion.
- Substantial Towing EGT Reduction: Relieves intense backpressure directly behind the downpipe, allowing scorching gases to exit rapidly to protect your turbo and engine under heavy towing.
- Permanently Stop DEF Limp-Mode Errors: Eliminates failure-prone DEF heaters, pumps, and NOx sensors that trigger automatic 55-MPH dealer Limp Mode lockouts.
- Full Downpipe-Back System: Replaces the entire restrictive mid-section and rusted OEM tailpipe from the turbo downpipe flange all the way to the rear exhaust exit.
FAQ
Q: What is the difference between a mid-pipe delete and this full Downpipe-Back kit?
A: A mid-pipe delete only replaces the under-cab DPF/SCR filters while forcing you to reuse your stock rear tailpipe. This Downpipe-Back kit replaces everything from the downpipe flange all the way to the rear quarter-panel exit—ideal if your original tailpipe or hangers are rusted out.
Q: Will this 3-Bolt flange Downpipe-Back kit fit an early 2011–2015.0 Duramax LML?
A: No. Early 2011–2015.0 LML trucks use a circular V-band clamp, This kit features a welded 3-hole triangular flange specifically made for Late 2015.5–2016 trucks. Attempting to fit this on an early model will cause severe bolt misalignment.
Q: Will this full system clear aftermarket gooseneck hitches or rear air helper bags?
A: Yes. The 4-inch mandrel-bent piping strictly adheres to GM's OEM exhaust clearance paths, leaving safe distance around under-bed gooseneck hitch frames and popular rear air helper spring kit.
Q: Can I add a performance muffler to this full system later if it feels too loud while towing?
A: Yes. The kit uses modular slip-fit connections with heavy-duty band clamps. If you ever want to tone down the straight-pipe sound, you can easily unclamp one of the straight extension pipe sections and slip in any standard 4" ID/OD high-flow performance diesel muffler.
