Flowmaster American Thunder 817664 User Manual

409S
®
Stainless Steel
Removal:
1) Raise the vehicle up on a hoist or rack to working height. If you do not have access to a hoist
or rack raise the vehicle and support securely with jack stands.
2) Using a 12mm socket, unbolt the tailpipe connection where it exits the muffler. Separate the
wire hanger on the tailpipe from the rubber mount on the vehicle. Remove the tailpipe and set aside.
3) Support the muffler with a stand, then using a 14mm socket unbolt the 4 bolts at the two front
flanged connections. Separate the wire hangers in front and rear of the muffler from the rubber
mounts on the vehicle. Remove the muffler inlet pipe assembly and set aside. Save the 4 factory
bolts, they will be reused in Installation step 1.
Installation:
1) Place the inlet pipes #86091S and #86092S into position, and fasten the flanged connections
together using the nuts, bolts and washers included in the hardware pack. Next, place the supplied
left inlet pipe clamp hanger #384HA and the right inlet pipe clamp hanger #353HA onto the inlet pipes
and into the factory rubber mounts on the vehicle.
2) Place two supplied 2 ½” clamps over the inlets of the muffler, and then slip the muffler onto the
back of the inlet pipes. Use a stand to support the muffler. Tighten clamps enough to hold in place
but still allow for adjustment.
3) Install the left rear frame hanger #354HA across from the center of the spare tire. Locate a
square cavity on the left rear frame rail. Look up into this cavity and locate the large hole at the top of
the frame. Install the #HA566 backing plate on the top side of the frame, then place the #354HA
hanger assembly up into the cavity using the washers and nut provided. Tighten the hanger firmly
using a 9/16” socket or wrench, slide the supplied rubber hanger #HA168 onto the end of the #354HA
hanger rod. Once the hanger assembly is bolted into place correctly it will face the rear of the vehicle
(see picture).
4) Place two of the supplied 2 ½” clamps over the outlets of the muffler; then place right tailpipe
#16543S into position over the rear axle, and slide into the right muffler outlet. Connect the hanger
that is welded to the rear of the pipe into the factory rubber hanger.
Installation Instructions for:
SYSTEM #817664
2009*-2014 TOYOTA TUNDRA TRUCKS
*BUILT AFTER 08/2008
4.6L & 5.7L V-8 I-FORCE ENGINES
*ALL EXCEPT STANDARD CAB/SHORT BED &
DOUBLE CAB/LONG BED*

Flowmaster American Thunder 817664 Specifications

General

Brand	Flowmaster
Model	American Thunder 817664
Category	Ventilation Hood
Language	English

Summary

Exhaust System Removal Procedure

Prepare Vehicle for Removal

Safely elevate and support the vehicle using a hoist or jack stands for optimal working height.

Remove Tailpipe

Disconnect the tailpipe at the muffler, detach its hanger, and remove it from the vehicle.

Remove Muffler and Inlet Pipe Assembly

Support the muffler, unbolt front flanges, detach hangers, and remove the muffler inlet pipe assembly.

Exhaust System Installation Procedure

Install Inlet Pipes and Hangers

Position inlet pipes, connect flanges using hardware, and attach clamp hangers to factory mounts.

Attach Muffler to Inlet Pipes

Secure the muffler to the inlet pipes using two 2 ½" clamps, allowing for adjustment.

Install Left Rear Frame Hanger Assembly

Mount the left rear frame hanger, backing plate, and rubber hanger onto the vehicle's frame rail.

Install Right Tailpipe

Connect the right tailpipe to the muffler outlet using clamps and attach its hanger to the factory mount.

Install Left Tailpipe Sections

Position left tailpipe sections, connect to muffler and each other, and attach hangers.

Install Exit Pipes and Tips

Attach side or rear exit pipes and stainless tips to muffler outlets, adjusting for fit and position.

Final System Adjustment and Tightening

Adjust all pipes for satisfactory fit, maintain 3/4" clearance, and securely tighten all connections.

Optional Welding for Enhanced Security

For increased security, welding of all slip-fit connections is highly recommended.