exhaust

Flex Pipe

for 2014 Ram 2500 6.7L I6 Cummins Diesel · 4WD

Difficulty

Moderate

Time

2.4 h

Tools

Steps

Replace the exhaust flex pipe on a 2014 Ram 2500 with 6.7L Cummins Diesel engine to restore exhaust system flexibility and eliminate leaks.

Warnings

⚠️Allow exhaust system to cool completely before beginning work. Exhaust components can remain hot enough to cause severe burns for over an hour after engine shutdown.

⚠Wear respiratory protection when working under the vehicle as rust and exhaust particulates may fall during disassembly.

⚠O2 sensors are fragile and expensive. Handle with care and avoid contamination with oil or grease.

ℹ️Exhaust fasteners are prone to corrosion. Apply penetrating oil 24 hours before beginning work if possible.

Tools required

Floor jack and jack standsEssential

Torque wrench (10-100 Nm range)Essential

Socket set (metric)Essential

O2 sensor socketEssential

Penetrating oil

Wire brush

Exhaust hanger removal tool

Anti-seize compound

Exhaust gasket scraper

Pry bar

Safety glassesEssential

Work glovesEssential

Parts

Exhaust flex pipe assembly × 1 — Use OEM specification
Exhaust flange gasket × 2 — Use OEM specification
Exhaust clamp (if applicable) × 1 — Use OEM specification

Preparation

Park vehicle on level surface and allow exhaust system to cool completely (minimum 2 hours after operation).
Disconnect negative battery cable to prevent electrical issues when handling O2 sensors.
Raise vehicle using floor jack and support securely on jack stands rated for vehicle weight. Ensure 4WD components are clear of jack points.
Spray all exhaust flange bolts, clamps, and hanger bolts with penetrating oil and allow to soak for 15-30 minutes.
Visually inspect flex pipe location between turbocharger outlet and exhaust downpipe to identify O2 sensor positions and mounting points.
Take reference photos of exhaust routing and hanger positions for reassembly.

Procedure

1
Remove upstream oxygen sensor
Locate the upstream oxygen sensor mounted before or on the flex pipe section. Disconnect the electrical connector by pressing the release tab. Using an O2 sensor socket, carefully unthread the sensor counter-clockwise. Inspect sensor threads for damage. If sensor is being reused, store in clean location away from contaminants.
2
Remove downstream oxygen sensor if applicable
If a downstream oxygen sensor is located on or immediately after the flex pipe section, disconnect its electrical connector and remove using O2 sensor socket. The 6.7L Cummins typically has sensors both before and after the DPF, so identify which sensors are affected by flex pipe removal.
3
Disconnect upstream exhaust flange
Locate the flange connection between the turbocharger downpipe and the flex pipe inlet. Remove the flange bolts using appropriate socket. There are typically 3 bolts in a triangular pattern. Support the flex pipe assembly with one hand while removing the final bolt to prevent it from dropping. Separate the flange connection and remove the old gasket.
Torque spec
Flange Bolts45 Nm (33 lb-ft)
4
Support exhaust system
Position a jack stand or suitable support under the exhaust system downstream of the flex pipe to prevent the exhaust from sagging or placing stress on downstream components during flex pipe removal. Adjust height so system remains level.
5
Remove exhaust hangers
Locate the rubber exhaust hangers supporting the flex pipe section. Using a pry bar or exhaust hanger tool, carefully pry the hangers off their mounting studs. Work methodically to avoid tearing the rubber isolators if they will be reused. Note the orientation of each hanger for reassembly.
6
Disconnect downstream connection
Identify the downstream connection method (flange or clamp). If flanged, remove the flange bolts and separate the connection. If clamped, loosen the exhaust clamp completely and slide it away from the joint. Maneuver the flex pipe to separate it from the downstream exhaust component.
Torque spec
Flange Bolts45 Nm (33 lb-ft)
Exhaust Clamps55 Nm (41 lb-ft)
7
Remove flex pipe assembly
With all connections released, carefully lower and remove the flex pipe assembly from the vehicle. The flex pipe may be heavier than expected due to accumulated soot and carbon. Inspect mounting points and adjacent exhaust components for damage or excessive wear.
8
Clean mating surfaces
Using a wire brush and gasket scraper, thoroughly clean all flange mating surfaces on both the turbocharger side and downstream pipe. Remove all old gasket material, carbon deposits, and rust. Ensure surfaces are flat and smooth to prevent exhaust leaks. Clean O2 sensor ports with wire brush if sensors are being reused.
9
Install new flex pipe assembly
Position the new flex pipe assembly into place, aligning it with both upstream and downstream connections. Install new exhaust flange gaskets on both ends. Loosely thread mounting bolts or position clamps but do not fully tighten yet. Ensure flex pipe is properly oriented with correct flow direction if marked.
10
Secure upstream flange connection
Install new flange gasket between turbocharger outlet and flex pipe inlet. Thread in all flange bolts finger-tight first to ensure proper alignment. Tighten bolts in a star pattern to specified torque to ensure even clamping pressure and prevent gasket distortion.
Torque spec
Flange Bolts45 Nm (33 lb-ft)
11
Secure downstream connection
Complete the downstream connection using appropriate method. If flanged, install new gasket and torque flange bolts in star pattern. If clamped, position clamp over joint ensuring it engages both pipe sections fully, then torque clamp bolts evenly.
Torque spec
Flange Bolts45 Nm (33 lb-ft)
Exhaust Clamps55 Nm (41 lb-ft)
12
Reinstall exhaust hangers
Reconnect all rubber exhaust hangers to their mounting studs. Ensure the exhaust system hangs naturally without binding or excessive tension. The flex pipe should have slight freedom of movement to accommodate engine torque and thermal expansion. Adjust positioning as needed before final tightening.
13
Reinstall oxygen sensors
Apply a thin coating of anti-seize compound to O2 sensor threads (avoid getting any on the sensor tip). Thread each O2 sensor into its port by hand first to prevent cross-threading. Torque sensors to specification using O2 sensor socket. Reconnect all electrical connectors ensuring they click securely into place.
Torque spec
O2 Sensor64 Nm (47 lb-ft)
14
Final inspection and alignment check
Visually inspect all connections to ensure proper alignment and gasket seating. Verify no exhaust components are contacting the frame, driveshaft, or other vehicle components. Check that all bolts and clamps are torqued properly. Remove support jack from under exhaust system. Reconnect negative battery cable.

Reassembly

Ensure all exhaust connections are properly torqued and aligned before lowering vehicle.
Verify oxygen sensor electrical connectors are fully seated and secured.
Check that exhaust hangers allow proper system movement without binding.
Confirm no exhaust components contact the driveshaft, frame, or suspension components through full range of motion.

Verification

Start engine and listen for exhaust leaks at all connection points. A hissing sound indicates a leak that must be corrected.
With engine running, visually inspect all flange connections and clamps for signs of escaping exhaust gases.
Allow engine to reach operating temperature and recheck all connections for leaks as thermal expansion occurs.
Check for diagnostic trouble codes related to oxygen sensors using scan tool. Clear any codes and verify they do not return.
Test drive vehicle and listen for abnormal exhaust noises, rattles, or vibrations that could indicate improper installation.
After initial test drive (approximately 20 miles), recheck all exhaust connection torque values as thermal cycling may cause settling.