The over-axle pipes on your 2005-2014 Mustang GT connect the mid-pipe to the axle pipe portion of your exhaust system. The name "over-axle" comes from the way that the pipes are routed over the axle of the vehicle. On factory over-axle pipes, Ford included a resonator to help tone down the exhaust, so for those who wanted a throatier-sounding exhaust, over-axle pipes without resonators is a go-to mod.
Purchase:
S197 Mustang Over Axle PipesStep 1: Begin the installation process by ensuring that the car is properly supported, either on a lift or jack stands, for safety.

Step 2: Pay attention to the tabs on the exhaust components, as these can become bent over time. Use a pry bar to gently straighten out any bent tabs.

Step 3: Locate the two sleeves that connect the over-axle pipe to the rear of the mid-pipe. These sleeves are crucial for securing the exhaust components.

Step 4: Using a 15-millimeter wrench, begin by loosening the nuts on the sleeves. If you encounter corrosion, consider soaking them in PB Blaster for easier removal.

Step 5: Leave one sleeve intact for now and proceed to loosen the clamp at the rear of the over-axle pipe using a 13-millimeter wrench on an extension.

Step 6: To avoid any movement, back up the sleeve you left intact earlier. This allows for easier maneuvering during the next steps.

Step 7: Note that if your car has a factory muffler, the clamp may be welded to it and won't move as shown. This is normal.

Step 8: If your car has a factory mid-pipe with a locating tab, use a flathead screwdriver to pry it open and slide the sleeve back. This tab is typically found on factory mid-pipes.

Step 9: With the necessary preparations complete, carefully lower the over-axle pipe over the axle and out of the car. Ensure you keep the sleeve or consider purchasing new ones.

Step 10: Match the new over-axle pipe to the old one, noting that they are side-specific (passenger and driver sides).

Step 11: Install the new over-axle pipe by reversing the removal procedure. Set the section of the over-axle pipe into the muffler, align it with the mid-pipe, and slide the clamp back into position.

Step 12: Begin tightening the clamp, but note that maneuvering may be required to ensure it aligns properly. Adjust as needed until it is in place.

Step 13: Snug down the clamp to secure the over-axle pipe in position.

Step 14: Reposition the sleeve to its original location. Tighten the nuts on the sleeves to secure the over-axle pipe.

Step 15: Check the alignment of the installed over-axle pipe with the other side, making any necessary adjustments for even placement.

Step 16: Fine-tune the clamp at the rear of the over-axle pipe for optimal positioning.
Step 17: Finally, give the entire installation a once-over, ensuring everything is properly aligned and tightened. If needed, perform similar steps for the other side of the exhaust system.
Remember that exhaust components can be somewhat tricky to position, and adjustments may be necessary to achieve the desired alignment. It can be helpful to have a friend assist with the process.