Quick Answer: How Do You Install an L5P DPF Delete Pipe?
Remove the factory Duramax L5P exhaust, install DPF Pipe #11711 at the front flange, fit the correct wheelbase extension, add Pipe #11212, Muffler Delete #40220, Over-Axle Pipe #11115, and Tailpipe #11716, then align and tighten the full system from front to rear. Keep every connection loose until all pipes are in place. Compatible tuning must be completed before operating a truck with monitored emissions parts removed.
Installing a 4-inch or 5-inch L5P DPF delete pipe is easier when you lay out every part before working under the truck. The most important rule is simple: keep the clamps and flange bolts loose until the complete exhaust is installed and aligned.
The main challenges are removing rusty factory hardware, selecting the right wheelbase extension, and keeping the over-axle pipe away from the suspension and body. Measure twice before cutting any extension pipe, and support each heavy exhaust section before releasing it.
Click to view the installation diagram and access the installation PDF document.
Confirm L5P Truck and Exhaust Fitment
This guide covers the installation layout used by the supplied L5P downpipe-back exhaust instructions. The linked race pipe is listed for 2017–2023 Chevrolet Silverado and GMC Sierra 2500HD and 3500HD trucks with the 6.6L L5P Duramax.
Do not order by engine name alone. Confirm the model year, cab, bed, wheelbase, factory exhaust layout, selected pipe diameter, and any previous exhaust changes. You can compare compatible exhaust and supporting parts in the 6.6L L5P Duramax collection.
| Fitment item | What to verify |
|---|---|
| Engine | 6.6L L5P Duramax diesel |
| Model year | Confirm the exact year against the selected product option |
| Truck | Chevrolet Silverado or GMC Sierra 2500HD/3500HD |
| Pipe diameter | Confirm whether the ordered system uses 4-inch or 5-inch pipe |
| Wheelbase | Measure before cutting or selecting an extension pipe |
| Previous changes | Check for an aftermarket downpipe, exhaust, hangers, or tuning |
What the L5P Downpipe-Back System Changes
The downpipe-back system replaces the exhaust behind the front connection and routes exhaust toward the rear of the truck. Based on the supplied instructions, the system uses a front Pipe #11711, extension pipes, Pipe #11212, Muffler Delete #40220, Over-Axle Pipe #11115, and Tailpipe #11716.
A less restrictive exhaust path can improve exhaust flow, reduce backpressure, support better turbo response, and create a deeper exhaust sound. Actual results depend on the truck, pipe size, tune, engine condition, and full setup.
The 2017–2023 L5P 4-inch and 5-inch DPF delete race pipe is the pipe-focused option for owners who already have a complete plan for the other required hardware and tuning. Verify the selected diameter and exact truck configuration before installation.
[[product-recommend:1]]
Tools and Supplies
Basic Hand Tools
- Metric and standard socket set
- Ratchet and extensions
- Combination wrenches
- Screwdrivers
- Pliers or exhaust-hanger removal pliers
- Torque wrench
- Penetrating oil
- Marker or paint pen
- Tape measure
Cutting and Installation Supplies
- Reciprocating saw with metal-cutting blades, if cutting is required
- Exhaust pipe cutter or cutting wheel
- File or deburring tool
- New gaskets and connectors required by the selected system
- Replacement clamps or hardware if the original parts are damaged
Safety Equipment
- Safety glasses
- Mechanic gloves
- Wheel chocks
- Rated ramps or jack stands
- A helper or exhaust support stand
Pre-Installation Checklist
- Confirm that the product, pipe diameter, and truck fitment match.
- Lay out every pipe in installation order.
- Match the visible pipe numbers to the supplied instructions.
- Check pipe ends, flanges, gaskets, hangers, and clamps for damage.
- Measure the truck’s wheelbase before cutting an extension.
- Apply penetrating oil to factory bolts, clamps, and hanger rods.
- Confirm the required tuning plan before removing monitored emissions parts.
- Save the complete factory exhaust and all removed hardware.
2017–2023 L5P 4 Inch DPF Delete Pipe Installation Steps
Step 1: Disconnect the Batteries and Support the Truck
Park on a level surface and let the exhaust cool. Set the parking brake, chock the wheels, and disconnect both negative battery cables before touching exhaust sensors or connectors.
Raise the truck only when more space is needed. Use approved lifting points and rated ramps or jack stands. Check that the truck is stable before getting underneath it.
Step 2: Disconnect the Factory Sensors and Lines
Trace the factory exhaust and find every electrical connector, sensor lead, pressure line, and metal hanger attached to the sections being removed. Label matching connections when needed, then disconnect them without pulling on the wires.
Do not cut, twist, or leave a sensor hanging by its wire. Follow the instructions for the exact product and tuning package when handling connections that will not return to the new exhaust.
Step 3: Remove the Factory Front Flange Hardware
Support the front exhaust section before removing its flange hardware. The original instructions identify four bolts at the front downpipe flange. Loosen them evenly and save reusable hardware that remains in good condition.
Next, remove the four bolts in the exhaust section near the catalytic converter, DPF, and torsion-bar crossmember area. Working space can be tight here, so use the correct socket and avoid rounding the bolt heads.
Step 4: Remove the Rest of the Factory Exhaust
Loosen the remaining clamps and support each exhaust section before removing its hanger. Apply a small amount of lubricant to the rubber isolators, then use pliers or an exhaust-hanger tool to slide out the metal hanger rods.
Lower the exhaust in manageable sections. Check every side before moving a pipe so it does not catch a wire, hose, heat shield, brake line, or crossmember.
Step 5: Cut the Factory Pipe Only If Needed
Not every truck requires the factory pipe to be cut. Cutting may make removal easier when there is not enough room to take the original system out in one piece.
Before cutting, inspect all sides of the pipe. Protect nearby wiring, brake lines, fuel lines, hoses, and the truck body. Make a straight cut and remove sharp edges with a file.
Step 6: Install Front Pipe #11711
Place the required gasket in the front flange connection. Position Pipe #11711 so its welded metal hanger enters the factory transmission isolator without pulling or twisting the rubber mount.
Align the pipe with the flange and install the four bolts loosely. The pipe must remain movable because its final angle will be set after the rest of the exhaust is in place.
Step 7: Fit Extension Pipes #40012 and #40018
Test-fit Extension Pipes #40012 and #40018 according to the truck’s wheelbase and supplied instructions. Do not cut an extension based only on cab or bed appearance. Measure the required installed length with the other pipes loosely positioned.
Mark the cut line, measure it again, and make a straight cut only when needed. Deburr the new edge so it slides into the next pipe without damaging the joint.
Step 8: Install Pipe #11212
Position Pipe #11212 and place its hanger in the factory location. Align it with Pipe #11711 and the correct extension section.
Slide the joints together with enough overlap for a secure clamp connection. Install the clamps loosely. Do not force a pipe into place or use the clamps to pull together parts that do not align.
Step 9: Install Muffler Delete #40220
Place Muffler Delete #40220 behind the front and extension sections. Insert its hanger into the correct factory rubber isolator, then connect it loosely to the exhaust.
Rotate the pipe until it follows the underside of the truck without contacting the frame, body, wiring, or nearby lines. Keep the clamp loose enough for later adjustment.
Step 10: Install Over-Axle Pipe #11115
Guide Over-Axle Pipe #11115 over the rear axle and connect it to the muffler-delete section. Insert the hanger into its factory isolator and check that the rubber mount is not stretched sideways.
Pay close attention to the axle, shock, spare tire, brake lines, parking-brake cables, and axle vent tube. Leave enough room for the axle to move as the suspension compresses and extends.
Step 11: Install Tailpipe #11716
Connect Tailpipe #11716 to the over-axle section and place its metal hanger in the factory isolator. Rotate the tailpipe until the outlet sits level and has safe clearance from the body.
Check the outlet at normal ride height when possible. Make sure exhaust flow is directed away from heat-sensitive parts and is not aimed at the tire or body panel.
Step 12: Align the Complete Exhaust
With every section installed loosely, start at Pipe #11711 and work toward the rear. Adjust pipe depth and rotation so the system follows the truck without putting sideways force on the front flange or rubber hangers.
Check clearance around the transmission, crossmembers, frame, driveshaft, axle, spare tire, wiring, hoses, and body. A pipe that clears while the truck is lifted may still touch another part at normal ride height.
Step 13: Tighten All Bolts and Clamps
Begin at the front flange and tighten the connections in stages as you move toward the tailpipe. Recheck alignment after each section. If one joint pulls the exhaust out of position, loosen it and realign the system.
Use the torque specification supplied with the exact product or clamp. Do not apply one generic torque value to every connection. Different bolts, flanges, and clamp styles may require different settings.
Post-Installation Checks
- Confirm that every flange, clamp, and hanger is secure.
- Make sure no tools or loose hardware remain under the truck.
- Verify that the required tuning process is complete.
- Reconnect both negative battery cables.
- Start the engine in a well-ventilated area.
- Listen for ticking, hissing, or puffing at every joint.
- Check for exhaust contact with the frame, axle, crossmember, body, wiring, or hoses.
- Watch for warning lights, fault messages, or reduced-power operation.
- Let the exhaust cool and recheck every connection after the first heat cycle.
- Inspect the system again after a short, low-load test drive where the truck can lawfully operate.
Common L5P Exhaust Installation Problems
| Problem | Likely cause | What to check |
|---|---|---|
| Pipe #11212 will not reach | Wrong extension, incorrect overlap, or wheelbase mismatch | Extension selection, measurements, pipe order, and joint depth |
| Front flange leaks | Damaged gasket or uneven flange alignment | Gasket position, flange faces, and bolt tightening sequence |
| Slip joint leaks | Low overlap, damaged pipe end, or poor clamp position | Joint seating, pipe shape, and clamp placement |
| Exhaust rattles | Pipe touches the frame, axle, crossmember, or body | Pipe rotation and clearance at normal ride height |
| Tailpipe sits too high or low | Front sections were tightened before final alignment | Loosen the system and realign it from front to rear |
| Rubber hanger is stretched | A pipe is rotated or positioned incorrectly | Hanger angle, pipe overlap, and front flange position |
| Warning light or reduced power | Missing, incomplete, or incompatible calibration | Stored codes, tune compatibility, and tuner instructions |
Race Pipe vs. L5P All-in-One Kit
A race pipe is the more focused choice when you already have the other required parts and a confirmed tuning plan. An all-in-one kit may be easier when the build also needs EGR-related hardware, tuning, or other supporting components.
| Option | Best for | CAN Bus Plug Kit |
|---|---|---|
| 4-inch/5-inch L5P race pipe | Owners who need the exhaust pipe and already have the rest of the build planned | Not presented as an all-in-one package |
| DPF/EGR/DEF All-in-One Kit | Owners who want a broader 2017–2023 L5P package | Not included |
| DPF/DEF/EGR All-in-One Kit with selectable options | Owners who need a broader package and want to select a CAN Bus Plug Kit option | Available as an option; confirm the selected configuration |
The 2017–2023 L5P DPF/EGR/DEF All-in-One Kit without a CAN Bus Plug Kit is the broader package when you do not need that plug kit. Do not assume a CAN Bus Plug Kit is included with this product.
[[product-recommend:2]]
If the build requires that part, compare the 2017–2023 L5P All-in-One Kit with a CAN Bus Plug Kit option. Check the selected product options before ordering because the CAN Bus Plug Kit is an available configuration, not something that should be assumed in every package.
[[product-recommend:3]]
Final Thoughts
A clean L5P exhaust installation depends more on patient alignment than speed. Install Pipe #11711 first, select and trim the wheelbase extension only after test-fitting, then build toward Tailpipe #11716 while keeping every connection loose.
Once all parts are in place, check clearance and tighten the system from front to rear. Complete the required tuning before operation, check for leaks after startup, and inspect the exhaust again after its first full heat cycle.
Find the Right Parts for Your L5P Duramax
Compare exhaust pipes, all-in-one packages, tuning options, and supporting parts for your L5P truck. Confirm the model year, engine, cab, bed, wheelbase, and selected kit contents before ordering.
FAQ
Q1: How long does it take to install an L5P DPF delete pipe?
A1: Installation time depends on rust, lifting equipment, wheelbase, and whether any pipe must be cut. A clean truck on a lift is usually much faster to service than a rusty truck on the ground.
Q2: Does an L5P DPF delete pipe require tuning?
A2: Yes. Compatible tuning must be addressed when monitored emissions hardware is removed from a vehicle that can lawfully use the setup. Do not operate the truck with an incomplete or unsupported calibration.
Q3: Do I need to cut the L5P extension pipe?
A3: It depends on the truck’s wheelbase and the selected exhaust configuration. Test-fit the complete system, measure the needed length, and cut only after confirming the correct extension.
Q4: Should I tighten the L5P exhaust clamps during assembly?
A4: No. Keep the bolts and clamps loose until every pipe is installed and aligned. Tighten the complete system from front to rear after checking clearance.
Q5: Why is my L5P exhaust pipe hitting the rear axle?
A5: The over-axle pipe may be rotated incorrectly, or the front sections may have been tightened too early. Loosen the clamps, realign the pipes, and check clearance through normal suspension movement.
Q6: What is the difference between a race pipe and an all-in-one L5P kit?
A6: A race pipe mainly covers the exhaust portion of the build. An all-in-one kit combines more required components, but the exact hardware and options vary by product.
Q7: Does every L5P all-in-one kit include a CAN Bus Plug Kit?
A7: No. One listed kit does not include a CAN Bus Plug Kit, while the other provides it as a selectable option. Verify the selected package before ordering.
Q8: What should I check after installing an L5P exhaust pipe?
A8: Check every joint for leaks, confirm safe clearance, watch for warning lights, and inspect the clamps and hangers after the first heat cycle.
Lars
Diesel Performance Engineer | 15+ Years Experience
"Empower Your Beast: Run Cooler, Pull Harder, Last Longer."
