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How to Install AFE Direct Fit Catalytic Converter - Front (04-06 4.0L Wrangler TJ) on your Jeep Wrangler

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CAUTION: Allow time for your vehicle to cool down prior to installation. When working on or under your vehicle proceed with caution. Exhaust systems reach high temperatures and may cause serious burns. Wear protective safety equipment; eye goggles and gloves to ensure a safe installation. aFe recommends professional installation on our products.

Step 1: Support the vehicle on jack stands disconnects the negative battery terminal from battery.

Step 2: Remove the O2 sensors between the FRONT & REAR of the OE cats.

Step 3: Remove the transmission cross member. USING A FLOOR JACK SECURE THE TRANMISSION and remove the nuts securing the cross member to the transmission.

Step 4: Remove the bolts on the cross member to the chassis and remove the cross member.

Step 5: Remove the (x2) nuts securing the catalytic converters to the stock exhaust system.

Step 6: Remove the (x4) 15mm bolts securing the catalytic converters to the stock exhaust manifold.

Step 7: Remove down pipe. Be careful when initiating this step removing the four bolts will cause the catalytic converters to fall so it is a good idea to have the help of a second hand when removing this down pipe.

Step 8: From the flange measure CUT 23.500" (See figure #1).

Step 9: Re-install OE Catalytic conveters to the OE exhaust system secure with the two nuts. NOTE: If you purchased the aFe POWER rear replacement (47-48004) you will need to cut 3.25” from the mid-pipe (See figure #2).

Step 10: Install aFe Direct Fit Cat Replacement using OE bolts to securing the catalytic converters to the stock exhaust manifold DO NOT TIGHTEN.


Step 11: Install the down pipe to the aFe cat replacement using (1x) 2.5" band clamp. Install down pipe to the OE catalytic converters using (x1) 2.5" band clamp, but DO NOT TIGHTEN the band clamps.

Step 12: Tighten the (x4)15mm bolts from step 6. Tighten the (x2) nuts from step 11. Tighten the band clamps

Step 13: Re-Install the cross member to transmission and the chassis using the original nuts and bolts and tighten

Step 14: the O2 sensors between the FRONT & REAR of the OE cats.

Step 15: Re-check all your work.

Step 16: Remove vehicle off jack stands.

Step 12: Re-check all bolts/nuts clamp after 50-100 miles.