Intermediate Pipe

Replacement of the intermediate exhaust pipe on a 1994-2007 Dodge Ram 2500 with 5.9L Cummins diesel engine, connecting the turbocharger downpipe to the muffler.

Warnings

Tools required

Parts

• Intermediate exhaust pipe × 1 — Use OEM specification or direct-fit aftermarket
• Exhaust flange gaskets × 2 — 3-inch flange gasket for Cummins
• Exhaust flange bolts/nuts × 6 — M10 x 1.5 stainless steel hardware recommended
• Exhaust hanger isolators × 2 — Replace if cracked or deteriorated

Preparation

1. Park vehicle on level ground and allow exhaust system to cool completely (minimum 2 hours after last operation).
2. Chock rear wheels securely.
3. Raise front of vehicle with floor jack and support on jack stands at frame rails behind front axle.
4. Spray all exhaust flange bolts and hanger bolts with penetrating oil and allow to soak for 30 minutes minimum.
5. Inspect intermediate pipe routing and identify all connection points: forward flange to downpipe, rear flange to muffler inlet, and rubber hanger mounts.

Procedure

1. 1

   Disconnect forward exhaust flange
   Locate the forward flange connection between the turbocharger downpipe and intermediate pipe (typically 3-bolt flange). Using the correct socket size (commonly 15mm or 18mm — verify on your vehicle) and breaker bar, remove the three flange bolts. The flange is located under the transmission bellhousing area. Support the intermediate pipe by hand or with a strap to prevent it from dropping when disconnected.
   ⚠Bolts may be heavily corroded. Apply heat carefully if necessary, avoiding fuel lines and wiring.
   Torque spec

   Exhaust Flange Bolt45 Nm (33 lb-ft)
2. 2

   Remove forward flange gasket
   Separate the forward flange and remove the old exhaust gasket. Use a wire brush to clean both mating surfaces on the downpipe flange and intermediate pipe flange, removing all carbon buildup and old gasket material. Inspect the downpipe flange for warping or damage.
3. 3

   Disconnect rear exhaust flange
   Move to the rear connection where the intermediate pipe connects to the muffler inlet pipe. This is typically located under the transmission or transfer case area. Using the correct socket size (verify on your vehicle), remove the rear flange bolts or loosen the band clamp, depending on your exhaust configuration. Support the muffler assembly to prevent strain on downstream hangers.
   ℹ️On 4WD models, the transfer case may limit access. Work from the driver's side for better clearance.
4. 4

   Detach exhaust hangers
   Locate the rubber exhaust hanger isolators supporting the intermediate pipe (typically one or two hangers along the length of the pipe). Using a pry bar or by hand, slide the pipe hanger rod out of the rubber isolator. You may need to push up on the pipe while pulling the rod sideways to release it. Mark hanger positions for reinstallation.
   Torque spec

   Hanger Bolts20 Nm (15 lb-ft)
5. 5

   Remove intermediate pipe
   With both flanges disconnected and hangers released, maneuver the intermediate pipe down and out from under the vehicle. The pipe may need to be rotated or angled to clear the transmission crossmember, transfer case, and frame rails. Remove the rear flange gasket and inspect.
6. 6

   Clean and inspect mounting points
   Thoroughly clean both flange mating surfaces on the downpipe and muffler inlet using a wire brush. Remove all carbon deposits, rust, and gasket material. Inspect rubber hanger isolators for cracks, tears, or deterioration and replace if necessary. Check that exhaust hangers welded to frame/body are secure and not broken.
7. 7

   Install new forward flange gasket
   Position a new exhaust flange gasket onto the turbocharger downpipe flange. The gasket should seat flat against the flange surface. Apply a light coat of anti-seize compound to the threads of new or reused flange bolts (avoid getting anti-seize on gasket sealing surface).
8. 8

   Position new intermediate pipe
   Lift the new intermediate pipe into position, aligning the forward flange first. The pipe may need to be angled to clear frame and drivetrain components. Loosely start the forward flange bolts by hand to hold the pipe in position. Do not tighten yet.
9. 9

   Install rear flange gasket and connect
   Position a new exhaust flange gasket onto the muffler inlet flange. Align the rear of the intermediate pipe with the muffler inlet flange. Apply anti-seize to the rear flange bolt threads and loosely install all bolts by hand. Ensure both flanges are aligned and gaskets are properly seated before tightening.
10. 10

    Install exhaust hangers
    Align the intermediate pipe hanger rods with the rubber isolator mounts. Push up on the pipe if necessary and slide the hanger rods into the rubber isolators. Ensure hangers are fully seated and the pipe is properly supported along its length without binding or strain.
11. 11

    Torque forward flange bolts
    Using a torque wrench and 15mm socket, tighten the forward flange bolts (connecting to turbocharger downpipe) to approximately 25-35 ft-lbs (verify exact spec for your vehicle) in a star or alternating pattern to ensure even gasket compression and proper seal. Verify anti-seize was applied to threads.
    Torque spec

    Exhaust Flange Bolt45 Nm (33 lb-ft)
12. 12

    Torque rear flange bolts
    Using a torque wrench and 15mm socket, tighten the rear flange bolts (connecting to muffler inlet) to approximately 25-35 ft-lbs (verify exact spec), or torque the band clamp per manufacturer spec if a slip-fit clamp is used, in a star or alternating pattern. Verify anti-seize was applied to threads. Double-check that gasket has not shifted during tightening.
13. 13

    Final inspection and clearance check
    Visually inspect all connections to ensure bolts are tight and gaskets are properly seated. Check clearance between the intermediate pipe and all surrounding components (frame, crossmembers, driveshaft, fuel lines, brake lines). The pipe should have at least 1/2 inch clearance from all components and should not contact anything when manually pushed or pulled. Verify hangers are supporting the pipe without excessive tension or compression.

Reassembly

1. Lower vehicle from jack stands carefully.
2. Remove wheel chocks.
3. Start engine and allow to reach operating temperature while monitoring for exhaust leaks at both flanges.
4. Listen for any exhaust contact or rattling noises that would indicate insufficient clearance.

Verification

• With engine running at operating temperature, inspect both flange connections for exhaust leaks (look for soot staining or listen for hissing).
• Check that exhaust system does not contact frame, body, or drivetrain components during engine idle.
• Perform a brief test drive and listen for any exhaust leaks, rattles, or vibrations.
• Re-check torque on all flange bolts after first heat cycle (after engine has cooled from test drive).
• Inspect hangers to ensure pipe is properly supported and not sagging or under tension.

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