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How it Installation?

Step 1 :

First, remove the passenger-side inner fender to provide sufficient operating space. It is also recommended to remove the grille assembly to prevent damage during downpipe removal or installation.

Step 2:

Remove the hex bolts securing the downpipe to the exhaust manifold. Then remove the sensor located directly above the hex bolts. The V-clamp connecting the front pipe and downpipe can also be removed. Keep the removed hex bolts, sensor, and V-clamp for later installation.

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Step 3:

Temporarily remove the exhaust front pipe, carefully disconnect the sensor, and loosen the four flange nuts at the rear of the front pipe. The transmission crossbeam needs to be temporarily lowered before removing the front pipe. Use a jack bracket to support the transmission before removing the transmission crossbeam. The exhaust front pipe also has a hanger mounted on the transmission, which also needs to be removed.

Step 4:

The heat shield on top of the turbine needs to be removed. A heat shield extending along the firewall at the rear of the downpipe also needs to be removed.

Step 5:

Carefully remove the two original sensors at the top of the downpipe, and also remove the original V-clamp. Keep both safe for future installation. This allows you to carefully slide the original downpipe out from between the chassis and transmission from under the vehicle or the passenger-side wheel arch.

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Step 6:

Begin installation now. First, insert the downpipe upwards from the bottom of the vehicle or the passenger side wheel arch. Align the flange with the turbocharger and install the V-clamp at the turbocharger. Do not tighten the clamp too much yet, leave some room for rotation.

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Step 7:

Loosely secure the downpipe to the exhaust manifold using the hex bolts on the original downpipe. Tighten the V-clamp at the turbocharger, then tighten the bolts on the exhaust manifold.

Step 8:

Install the original sensors onto the downpipe. One sensor is located at the bottom of the downpipe. The other two sensors are near the turbocharger.

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Step 9:

The front exhaust pipe can then be reinstalled using the original hardware and V-clamps.

Step 10:

Reinstall the exhaust pipe hanger onto the transmission crossbeam. Reinstall the transmission crossbeam. Reconnect all sensors to the front exhaust pipe.

Step 11:

Reinstall the turbocharger heat shield. Inspect the exhaust pipe, ensuring all connections are tightened. Inspect the entire exhaust system, ensuring sufficient clearance around the spare tire, fuel lines, brake lines, or any wiring. If any obstructions are found, reposition or adjust them.
After inspection, reinstall the passenger-side inner fender.

TruckTok 2011-2015.5 Chevy/GMC 6.6L Duramax LML Turbo Diesel 3Inch Downpipe Exhaust
0%, only 810 left
TruckTok 2011-2015.5 Chevy/GMC 6.6L Duramax LML Turbo Diesel 3Inch Downpipe Exhaust
TruckTok 2011-2015.5 Chevy/GMC 6.6L Duramax LML Turbo Diesel 3Inch Downpipe Exhaust
TruckTok 2011-2015.5 Chevy/GMC 6.6L Duramax LML Turbo Diesel 3Inch Downpipe Exhaust
TruckTok 2011-2015.5 Chevy/GMC 6.6L Duramax LML Turbo Diesel 3Inch Downpipe Exhaust
TruckTok 2011-2015.5 Chevy/GMC 6.6L Duramax LML Turbo Diesel 3Inch Downpipe Exhaust
TruckTok 2011-2015.5 Chevy/GMC 6.6L Duramax LML Turbo Diesel 3Inch Downpipe Exhaust
TruckTok 2011-2015.5 Chevy/GMC 6.6L Duramax LML Turbo Diesel 3Inch Downpipe Exhaust

TruckTok 2011-2015.5 Chevy/GMC 6.6L Duramax LML Turbo Diesel 3Inch Downpipe Exhaust

$134.25

FITMENT

  • 2011-2015.5 6.6L Silverado & Sierra Duramax 2500HD/3500HD with LML Diesel engine pickup.
  • This downpipe features a V-Band connection flange at the turbo outlet.
  • NOT directly fit 2015.5-2016 models with the 3-bolt flange exhaust system unless the downstream system is modified.

DESCRIPTION

Product Overview

  • The factory downpipe on 11-15.5 Duramax LML trucks is a major performance bottleneck. To squeeze past tight engine bay clearances, GM engineers severely crushed and flattened the stock pipe.
  • This restricted "pancake" design chokes exhaust flow, traps excessive thermal energy right at the turbo charger, and spikes EGTs under heavy towing loads.
  • Upgrading to smooth, 3-inch mandrel-bent downpipe maximizes exhaust flow right from the turbo outlet, rapidly dropping EGTs and allowing the turbo to spool up much faster.

Key Features

  • Heavy-Duty Wrapped Protection: Crafted from high-grade 304 stainless steel and wrapped in premium heat-insulating sleeve to safeguard surrounding engine bay components.
  • TIG-Welded Construction: All joints are precision TIG welded and jig-built to prevent cracking under high thermal cycling and aggressive vibration.
  • Unrestricted 3" Bore: Replaces the restrictive, "crushed" factory oval pipe with a true, consistent 3“ mandrel-bent round diameter through every turn.
  • Drastic EGT Reduction: Smooths out exhaust flow to quickly draw extreme heat away from the turbo, reducing under-hood temperatures and protecting engine health.

FAQ

Q: Will this fit my 2015 or 2016 model?

A: It fits 11-15.5 models that use a V-band style turbo connection. In 15.5-16, GM switched the LML to a 3-bolt flange style downpipe. Please inspect your truck's connection before buying.

Q: Does this pipe have the necessary sensor ports?

A: Yes. Unlike older generations, the LML downpipe requires sensor ports. This downpipe is precision-engineered with 3 factory-location bungs to house your stock EGT sensor, NOx sensor, and 9th injector dosing valve flawlessly.

Q: What happens to the sensor bungs if I delete my truck?

A: If you are doing an emissions delete and removing these sensors, you must buy a standard LML downpipe plug kit (or sourcing matching bolts/plugs) to cap the 3 bungs off so exhaust gas doesn't leak out.

Q: Will this 3" downpipe work with my stock exhaust or an aftermarket 4"/5" delete pipe?

A: Yes, it fits both perfectly. The OEM-matched flanges bolt directly to the stock turbo and factory exhaust. If you upgrade to a 4" or 5" delete pipe, it still fits flawlessly—all downpipe-back systems neck down to bolt directly to this factory location without adapters.

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