Catalytic Converter: Service and Repair
Catalytic Converter
Special Tool(s)
Material
Removal
CAUTION: Do not use oil or grease-based lubricants on the isolators. They may cause deterioration of the rubber.
CAUTION: Oil or grease-based lubricants on the isolators may cause the exhaust hanger isolator to separate from the exhaust hanger bracket during vehicle operation.
NOTE: Exhaust fasteners are of a torque prevailing design. Use only new fasteners with the same part number as the original. Torque values must be used as specified during reassembly to make sure of correct retention of exhaust components.
1. With the vehicle in NEUTRAL, position on a hoist.
2. Remove the transfer case skid plate if equipped.
3. Remove the muffler-to-exhaust pipe exhaust clamp.
4. Disengage the muffler from the 3 isolators and remove the muffler.
5. Remove and discard the extension pipe-to-Y-pipe exhaust coupler.
6. Remove and discard the extension pipe.
7. Grind the spot weld, then remove and discard the LH catalytic converter-to-Y-pipe exhaust clamp.
8. Disconnect the 2 catalyst monitor sensors electrical connectors and the 2 heated oxygen sensors electrical connectors.
9. If installing a new converter, use the special tool and remove the 2 catalyst monitor sensors and the 2 heated oxygen sensors.
10. Using a jackstand, support the catalytic converters.
11. Remove the 2 catalytic converter hanger bracket bolts.
12. Remove and discard the 4 catalytic converter-to-manifold nuts.
13. Index-mark the front driveshaft flange and the driveshaft yoke.
14. Remove the 4 driveshaft yoke bolts.
15. CAUTION: The driveshaft flange fits tightly on the rear axle pinion flange pilot. ever hammer on the driveshaft or any of its components to disconnect the driveshaft flange from the pinion flange. Pry only in the area shown, with a suitable tool, to disconnect the driveshaft flange from the pinion flange.
Using a suitable tool as shown, disconnect the driveshaft from the flange.
16. Position the driveshaft aside and support with mechanic's wire.
17. Remove the LH exhaust shield bolt.
18. CAUTION: Do not damage the manifold outlet flare, the converter inlet flare or the studs.
Support the LH catalytic converter near the rear outlet, then remove the catalytic converter.
19. Remove the RH exhaust shield bolt.
20. CAUTION: Do not damage the manifold outlet flare, the converter inlet flare or the studs.
Support the RH catalytic converter near the rear outlet, then remove the catalytic converter.
21. If necessary, remove the exhaust hanger bracket bolts.
22. If necessary, remove the exhaust hanger brackets.
23. If necessary, remove the catalytic converter isolator.
24. If necessary, remove the catalytic converter hanger bracket.
Installation
1. If removed, install the catalytic converter hanger bracket and bolts.
^ Do not tighten until the exhaust system has been aligned.
2. If removed, install the catalytic converter isolator.
3. If removed, install the exhaust hanger brackets and bolts.
^ Tighten to 20 Nm (15 ft. lbs.).
4. CAUTION: Do not damage the manifold outlet flare, the converter inlet flare or the studs.
NOTE: Do not tighten the fasteners until all components are assembled.
NOTE: Clean the mating surfaces of the manifold outlet flare and the catalytic converter inlet flare prior to installation.
Install the RH catalytic converter.
^ Do not tighten the nuts until the exhaust system has been aligned.
5. Remove the RH exhaust shield bolt.
^ Tighten to 15 Nm (11 inch lbs.).
6. CAUTION: Do not damage the manifold outlet flare, the converter inlet flare or the studs.
NOTE: Do not tighten the fasteners until all components are assembled.
NOTE: Clean the mating surfaces of the manifold outlet flare and the catalytic converter inlet flare prior to installation.
Support the RH catalytic converter near the rear outlet, then install the LH catalytic converter.
Do not tighten the nuts until the exhaust system has been aligned.
7. Remove the RH exhaust shield bolt.
^ Tighten to 15 Nm (11 inch lbs.).
8. CAUTION: If new driveshaft yoke bolts are not available, coat the threads of the original bolts with Threadlock and Sealer.
Using the index marks as a guide, position the driveshaft and install the 4 bolts.
^ To install, tighten the bolts to 112 Nm (83 ft. lbs.) evenly in a cross pattern.
9. NOTE: Apply anti-seize lubricant to the threads of the sensors before installation.
If installing a new converter, use the special tool and install the 2 heated oxygen sensors.
^ To install, tighten to 40 Nm (30 ft. lbs.).
10. NOTE: Apply anti-seize lubricant to the threads of the sensors before installation.
If installing a new converter, use the special tool and install the 2 catalyst monitor sensors.
^ To install, tighten to 40 Nm (30 ft. lbs.).
11. Connect the 2 catalyst monitor sensor electrical connectors and the 2 heated oxygen sensor electrical connectors.
12. Position a new exhaust clamp onto the Y-pipe and connect the LH catalytic converter to the Y-pipe.
13. Position the new clamp over the pipe Joint. Make sure the back of the slot is covered by the clamp. The clamp is installed no more than 4 mm (0.16 inch) from the back of the button on the end of the pipe.
^ Do not tighten the clamp until the exhaust system has been aligned.
14. Install the muffler into the isolators.
15. Position a new exhaust coupler onto the extension pipe.
16. Install the extension pipe.
17. NOTE: Do not tighten the coupler until the exhaust system has been aligned.
Position the new exhaust coupler over the extension pipe-to-Y-pipe.
18. Position a new exhaust clamp onto the extension pipe.
19. Install the muffler. Make sure the button on the muffler inlet pipe is fully seated inside the L-notch on the extension pipe before tightening the exhaust clamp.
^ Do not tighten the clamp until the exhaust system has been aligned.
20. Position the new clamp over the pipe Joint. Make sure the back of the slot is covered by the clamp. The clamp is installed no more than 4 mm (0.16 inch) from the back of the button on the end of the pipe.
21. Align the exhaust system.
22. If removed, install the transfer case skid plate.