Downpipe

This procedure covers removal and replacement of the exhaust downpipe on a 2007 Ram 3500 with the 5.9L Cummins diesel engine, connecting the turbocharger outlet to the exhaust system.

Warnings

Tools required

Parts

• Downpipe to turbo gasket × 1 — Use OEM specification
• Downpipe flange gasket × 1 — Use OEM specification
• Exhaust manifold nuts (if damaged) × 4 — Use OEM specification
• Exhaust clamp or flange bolts × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and apply parking brake
2. Chock rear wheels securely
3. Allow engine and exhaust system to cool completely (minimum 2 hours after operation)
4. Apply penetrating oil to all downpipe fasteners, turbo outlet nuts, and exhaust clamps. Allow to soak overnight if possible
5. Raise front of vehicle and support securely on jack stands
6. Remove passenger side front wheel for improved access
7. Disconnect negative battery terminal to prevent electrical issues while working

Procedure

1. 1

   Disconnect exhaust temperature sensor
   Locate the exhaust gas temperature (EGT) sensor on the downpipe if equipped. Note: this diesel engine does not use an oxygen sensor for fuel control. Disconnect the electrical connector by pressing the release tab and pulling straight out. If sensor will be reused, carefully remove the EGT sensor using an appropriately sized wrench or deep socket to avoid damaging the threads.
2. 2

   Remove exhaust clamp at downpipe outlet
   Locate the band clamp or bolted flange connection where the downpipe connects to the intermediate exhaust pipe. For band clamp: use 14mm or 15mm socket to loosen clamp nut and remove clamp. For bolted flange: remove the two or three flange bolts using appropriate socket. Spray connection with additional penetrating oil if stuck.
   ⚠Exhaust clamps may be severely corroded. Be prepared for clamp to break during removal and have replacement available.
3. 3

   Support downpipe weight
   The downpipe is heavy and awkwardly positioned. Position a floor jack with a block of wood under the downpipe to support its weight before removing mounting hardware. This prevents the pipe from falling or binding during removal.
4. 4

   Remove downpipe hanger bracket
   Locate the downpipe support bracket that attaches to the transmission or bellhousing. Remove the bracket mounting bolt(s) using 13mm or 15mm socket. If bracket is welded to downpipe, it will come off with the pipe assembly.
5. 5

   Remove turbo outlet to downpipe fasteners
   Working from above and below the vehicle, locate the V-band clamp or the four nuts securing the downpipe to the turbocharger outlet. For V-band clamp: loosen the 13mm or 14mm bolt and remove clamp. This engine uses a V-band clamp at the turbo outlet: loosen the V-band clamp bolt and remove the clamp. Apply heat carefully if fasteners will not break free, being mindful of nearby components. The V-band clamp may be corroded and seized. Be prepared for the clamp to be difficult to remove and have a replacement available.
   ⚠Seized fasteners may cause studs to break. If studs break, they must be extracted from turbo housing before reinstallation.
6. 6

   Maneuver downpipe free
   With all fasteners removed, carefully work the downpipe down and away from the turbo outlet. May require rotation and angling to clear steering components, transmission crossmember, and frame rails. Lower the jack slowly while guiding the pipe. If pipe is seized to turbo outlet, carefully tap the downpipe flange with a hammer and pry bar to break seal.
7. 7

   Clean mounting surfaces
   Using a wire brush and gasket scraper, thoroughly clean the turbocharger outlet flange surface, removing all old gasket material and carbon deposits. Clean the downpipe flange at the intermediate pipe connection. Inspect turbo outlet studs for damage and replace if threads are stripped or studs are bent. Wire brush the studs and apply anti-seize compound.
8. 8

   Prepare new downpipe
   If installing aftermarket downpipe, verify it matches the original routing and mounting points. Install new turbo outlet gasket onto the turbo flange or downpipe inlet as designed. If reusing oxygen sensor or EGT sensor, apply anti-seize to threads and install into new downpipe. Do not overtighten sensors.
9. 9

   Install downpipe to turbo
   Raise the downpipe into position using the floor jack and wood block for support. Align the inlet flange with the turbocharger outlet flange, ensuring gasket is properly positioned. Start all fasteners by hand first. For studded connection: thread on all four nuts by hand. For V-band clamp: position clamp around flanges. Verify downpipe is hanging correctly before tightening.
10. 10

    Tighten turbo outlet connection
    For the V-band clamp: tighten the clamp bolt gradually while ensuring the clamp stays centered on the flanges. Torque to approximately 8-10 ft-lbs, but verify with manufacturer specifications. Do not over-torque. For V-band clamp: tighten clamp bolt firmly, ensuring clamp is centered on flanges. Do not over-torque which can damage gasket.
11. 11

    Install downpipe support bracket
    Attach the downpipe support bracket to the transmission or bellhousing mounting point. Tighten bracket bolt securely. Verify downpipe is not under stress or binding before final tightening.
12. 12

    Connect downpipe to intermediate pipe
    Install new gasket or seal at the downpipe outlet connection. Slide intermediate pipe into position and install new band clamp or install flange bolts. For band clamp: tighten to 35-45 ft-lbs. For flange bolts: tighten in alternating pattern to 25-30 ft-lbs. Ensure connection is fully seated before tightening.
13. 13

    Reconnect exhaust sensor
    Reconnect the electrical connector to the EGT sensor if equipped. Ensure connector clicks into place and is secure. Route wiring away from hot exhaust components and moving parts.

Reassembly

1. Reinstall passenger side front wheel and torque lug nuts to manufacturer specification (typically 135 ft-lbs for Ram 3500)
2. Lower vehicle from jack stands
3. Reconnect negative battery terminal
4. Remove wheel chocks

Verification

• Start engine and allow to idle. Listen for exhaust leaks at turbo outlet connection and downpipe joints
• Check for exhaust smoke or visible leaks at all connections while engine is running
• Rev engine slightly and recheck all connections for leaks
• Take vehicle for short test drive and verify no exhaust leaks under load
• After test drive, recheck all fastener tightness while exhaust is warm
• Verify check engine light does not illuminate if oxygen sensor or EGT sensor was disturbed
• Monitor exhaust gas temperature readings if equipped with EGT gauge to verify sensor is functioning

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