Roush Axle-Back Exhaust Stainless Steel GT 2015-2017

Roush: 421834
MSRP: $599.99
CJ's Low Price:
1508630400 57949
Add this Clamp-In Stainless Steel Tru-X Resonated X-Pipe to your order for your 2015-2017 Mustang GT!
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Roush Axle-Back Exhaust Stainless Steel GT 2015-2017
Roush Axle-Back Exhaust Stainless Steel GT 2015-2017 Roush Axle-Back Exhaust Stainless Steel GT 2015-2017 Roush Axle-Back Exhaust Stainless Steel GT 2015-2017 Roush Axle-Back Exhaust Stainless Steel GT 2015-2017 Roush Axle-Back Exhaust Stainless Steel GT 2015-2017 Roush Axle-Back Exhaust Stainless Steel GT 2015-2017 Roush Axle-Back Exhaust Stainless Steel GT 2015-2017 Play Roush Axle-Back Exhaust Stainless Steel GT 2015-2017 Video 1 Play Roush Axle-Back Exhaust Stainless Steel GT 2015-2017 Video 2

Product Description

Roush Stainless Steel Axle-Back Exhaust for all 2015, 2016 and 2017 GT Mustangs.

The Roush stainless steel axle-back exhaust (P/N: 421834) is designed to fit all 2015-2017 GT Mustangs and will offer every owner the opportunity to install one of the most popular systems in the market today!

Roush’s stainless steel axle-back exhaust is the segment of your exhaust system that sits behind the rear axle, which is how it gets its name. It can even give you that classic muscle car roar that you’ve always wanted for your high-performance Mustang. This axle-back exhaust from Roush will offer your 2015-2017 Mustang GT a distinct and aggressive sound. The highly tuned system will avoid the annoying drone or rasp that can occur with other competitive exhaust systems on the market. Needless to say, you will love the unmistakable sound and efficiency of your quality, new exhaust.

Backed By Popular Opinion and High-Quality Results

Constructed from 304 Stainless Steel, this axle back exhaust system features an exclusive open-chambered design that will not deteriorate over time, unlike conventional fiberglass packing material. The round exhaust tips are also made from stainless steel and finished with a unique process that provides heat resistance to color change. Like all Roush products, installation is quick, easy, and uses all factory hanger locations. The only necessary modification to the vehicle is that the factory exhaust will need to be cut off so that the new Roush axle-back can easily install with the provided clamps.

When you buy this axle-back exhaust, you get more than just a dependable exhaust system.

Features and Benefits:
- Fills OEM Ford Rear Valance
- Zero Impact on Emission Devices
- Straight-Thru Design Yields Higher Airflow and Performance 
- Full 304 Stainless Steel Construction
- Includes Clamps and Installation Instructions

*Installation requires cutting of the factory exhaust piping. Once the modifications have been made to the factory exhaust system, Installation is a simple bolt-in procedure.

How well do you want your Mustang to look and perform? With any of the parts from Roush Performance, you can give it a major performance overhaul, and add some visual styling that will make your Mustang stand apart from the crowd. CJ Pony Parts is a Roush Top 10 Dealer and offers parts from Roush Performance for many different years of Mustang, many of which are in stock and ready to ship today.

Manufacturer Part Number: 421834

If you want a great exhaust that will improve the performance of your ride and give you that signature muscle car roar, then this Roush axle-back exhaust is for you. Plus, we offer all of our products at some of the lowest prices on the market so you can get the products you need in no time. Best of all, when you order before 5 PM EST, we can get your purchase on the road that same day, and we can almost always do it for free! Get the Roush Stainless Steel Axle-Back Exhaust for your 2015-2017 Mustang GT from CJ Pony Parts today!

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Mustang Applications

This product will fit the following Mustang years:

Product Reviews

Write a review
Roush Axle-Back Exhaust Stainless Steel GT 2015-2017 is rated 4.9 out of 5 by 106.
Rated 5 out of 5 by from Awesome Bought the Roush Axel Back exhaust. ordered it on Tuesday Ground UPS nad received it in two days. Installed it the same day I received it. Took exactly 1 hour to install. I can't beleive the sound. Roush has a special sound that is not like others. The Tips have the Roush Name on them. My car used to turn heads without the Mufflers Now it really turns heads. The video was spot on accurate and was the deciding facter in me purchasing. If you are concerned they may not be Loud enough after listening to the Video's , Think again, I left the resonator on and just just the Pipes. When you get on it, ITS LOUD! Crusing speeds you can barely hear it.
Date published: 2015-10-17
Rated 5 out of 5 by from Amazing sound! I actually bought these used from someone for my 2016 gt PP stick and I already had an frpp xpipe and only engine mod is a k&n drop in filter. Let me just say that I have had many exhaust systems before on various cars, but this setup is by far my favorite! There is no drone at all at 80 in 6th. The exhaust sounds really good and not obnoxious when throttle is below 50%, but once you get on it, it gets like 5 times louder and absolutely amazing. You will not regret this system with an x pipe. Haven't tried it with an h pipe because I didn't want to be too loud and was worried about drone. I would definitely by another Roush product after this one.
Date published: 2016-03-05
Rated 5 out of 5 by from Amazing Sound and easy install Delivered yesterday and with the help of my wife, installed them last night in garage. I actually did not use a jack or lift, just reached under the car after I did the measuring and the sawsall did the all the work. Seriously, it only took us about 25 minutes from start to finish to install the axle-back system on our 2016 GT Convertible. We immediately took her (Ruby...wife nicknamed the car) out for a spin. The sound is amazing, not raspy or obnoxious, but a deep throaty, strong sound. Fast shipping from CJ Pony Parts and amazingly easy install from Roush. Admittedly a bit pricy, but I bought it for the quality. Great well made Product.
Date published: 2016-11-11
Rated 5 out of 5 by from Easy install and great sound! Had this on the car for almost a month and it sounds great! Install was easy and straight forward. I was able to use a lift so it made it easy. Solid product and awesome sound!
Date published: 2015-02-07
Rated 5 out of 5 by from What a sound! I ordered this Roush Axle-Back exhaust when I thought my car was being delivered to Australia in December last year. Suffice to say that delivery was excellent from CJPonyParts, with it being sent from the US to the west coast of Australia in only 10 days, and just before Xmas too!!. Amazing service. Turns out delivery of the car was delayed for 5 more months! Picked it up a few days ago. Installation (which occurred in my garage with some simple jacks) should have been a breeze, however it appears that the Australian version of the icon comes with the underbody covered in a layer of black paint!! Suffice to say that this needed to be sanded off the end once the exhaust pipe was cut to allow the new Roush exhaust to be installed. Another tip, make sure that you have the right number of teeth on your sawzall (we call it a reciprocating saw here in Oz!) blade. It makes the difference between a struggle and cutting knife through butter... Nevertheless, all was forgiven once the car was started. The sound has to be heard to be fully appreciated. Even the video does not do it justice when it is under load at 5000rpm. It is phenomenal!! I do not hesitate in fully recommending this exhaust system to anyone. Thanks to Bill at CJ Pony Parts for making it easy to choose and install with your awesome videos on your website! Great job
Date published: 2016-04-03
Rated 5 out of 5 by from Great sound, perfect volume with stock resonator! Very happy with this exhaust! Sounds great and looks great... I kept my stock resonator in place and the volume level is perfect for me. You will love it.
Date published: 2015-02-06
Rated 5 out of 5 by from That V8 Growl I combined this exhaust system with a Ford Racing Resonator Delete pipe and boy does it make a huge difference. Roush, in my opinions has always had the best exhaust tone compared to all the other axle backs out there. CJ Pony Parts shipped and delivered this in 1 day since I live on the east coast. Couldn'tbe happier with my purchase.
Date published: 2015-02-06
Rated 5 out of 5 by from Great sound Bought this with the H pipe for my son's 2015 GT performance package mustang; we backed the car up on ramps, you can reach the 4 bolts on the clamps for the resonantor; after loosening those for bolts we unbolted the rear hangers, they have clips that hold them up until you're ready to drop the exhaust, but first we used a floor jack with a strip of wood to support the exhaust just behind the resonantor then drop the hangers and lower the floor jack to pull out to exhaust, then measure twice and cut were needed; test fit everything, we used some anti-seize, reinstall in sections using the floor jack to support the pipes.
Date published: 2015-12-14
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Product Questions

Do you guys know or deal with any shops out of Louisiana? I would love to buy this set up for my vehicle but I'm rather nervous about having a random shop cut into my exhaust. Any recommendations?

Asked by: sriley4723
We do not have any shop recommendations to offer. But what I can tell you is that any competent exhaust shop will be able to handle this installation without any issues. This is something that most people can even handle in their driveway in very little time with basic hand tools and a saw. Axle-back installations on the S550 are a walk in the park.
Answered by: CJPP Dave
Date published: 2017-09-10

Do I need a tune after install? and what about with an x pipe too if I install together, would I need a tune also?

Asked by: Ben colon
This does not require a tune. If using the Roush 422046 x-pipe it will not require a tune.
Answered by: rk cjpp
Date published: 2017-07-27

I have been buying nearly all my car parts from CJ Pony the last few years. I would like to buy the Roush Axle-Back Exhaust Stainless Steel GT 2015-2017 w/ BLACK tips which is readily available on Amazon. Can CJ get me this muffler combination?

Asked by: Mustang 1966 and 2015
This system is NOT available with Black Tips. If you have found it on Amazon or any 3rd party retailer, they are coating the tips for resale. That option does not come directly from Roush.
Answered by: CJPP Dave
Date published: 2017-07-27

Hi, I am looking to get this Roush Axle-back set up first and then an H pipe later on down the road. My question is this. Later down the road when I add the H pipe, will there be an issue with re clamping the Roush system to the H pipe?

Asked by: Adamwho2
No, they do not clamp together. There will still be a section of your original piping between the two. What you are trying to do will work perfectly fine.
Answered by: CJPP Dave
Date published: 2017-07-27

would you deliver to Australia and if so what would be the cost for mailing, how long will it take to reach me and the complete cost of item and postage. Thanks

Asked by: MMMustang
We ship worldwide, to get a shipping quote and total price, add the item(s) to your shopping cart and then proceed to checkout. In checkout, fill out your address info and scroll down to see shipping options and costs to your area including any import taxes and duties.
Answered by: CJPP Dave
Date published: 2016-12-19

Will this exhaust fit the 2016 convertible?

Asked by: rickwalden61
Answered by: CJPP Dave
Date published: 2016-12-08

i have the mishimoto axel back set on now (muffler delete), was going to change to the roush axel back. do I have to recut my exhaust or will the previous cuts for the mishimoto match up for the roush install?

Asked by: Jims stang
That is hard to say. Most axle-backs require you to cut in a different location. We have not gone from the Mishimoto to the Roush or the opposite on any test fitments.
Answered by: CJPP Dave
Date published: 2016-11-28

hi, is the roush axle back exhaust loud at idle or for normal driving. My dad bought a mustang and it is too quiet but he doest want it loud or expensive

Asked by: brodden01
Exhaust sound and volume is subjective, I can't answer that question for you. My definition of loud may be different from yours or your dads. We have several videos to help customers make an informed decision and there are plenty reviews where customers talk in detail about the sound and volume of this exhaust.
Answered by: CJPP Dave
Date published: 2017-02-21
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Product Video

Roush Axle-Back Exhaust Stainless Steel GT 2015-2017 Video Transcript
By Bill Tumas: The Roush axle back was one of the more popular systems for the 2011 through 2014 Coyotes, especially if you keep the rest of your exhaust system stock. It offered a very aggressive tone when on the throttle, but at highway speeds it was very tame and offered no drone at all. When Roush announced a similar system for the 2015 Mustang, we knew we had to get our hands on one, so today we're going to show you how to install one on your 2015 Mustang, and we'll provide you some sound clips.

Unlike the previous models, any axle back on the 2015 Mustang will require cutting, which actually isn't that big of a deal. The system comes with everything you need for installation, including the two mufflers, which are full stainless steel along with these two chrome four-inch tips. Before we get started with the installation, we're going to play you some sound clips of a factory 2015 GT exhaust.

For this installation, a lift or a jack and jack stands, half-inch ratchet or low torque electric half-inch impact gun, 15 millimeter socket, Sawzall, file, marker, and safety glasses. Like I said, with any axle back system, you're going to have to cut. Previous models would have clamps in this neighborhood, but in the case of the 15's, everything is welded. But cutting really is no big deal.

The instructions from Roush are very clear on where to cut, so you want to mark it over here. I'll explain where you're actually going to mark it and then you can cut it. The instructions provided by Roush tell you to cut the pipe closest to the tangent of the curve. If you're like me, you probably read more car magazines than paid attention in geometry class. I'll explain what the tangent is. What that is, is the closest straight line to the curve of the pipe. You want to follow the curve over and as soon as it gets to a straight section, that's roughly where you're going to cut. Do the same thing on both sides. To make sure you're in the right neighborhood, grab the Roush muffler. You're going to hold it up approximately where it's going to go. Then make sure this lines up with where you're going to cut.

Everything looks good, so we can cut the pipe. Since you'll need two hands to control the saw, if you don't have someone to hold the pipes for you, stuff some rags up in here. That way, it doesn't bounce up against your balance. Now we can slide the muffler off the factory hanger. Then you'll want to de-burr it before we put the new pipe on. First, slide the clamp over our muffler, make sure it's a spot where you can reach in to tighten it. I'm going to put it up into the hanger and slide it over the factory pipe. Now grab the supply tips that are fully adjustable in this case. Slide a clamp on, and make sure you get it where you want it. You can push it all the way down and bottom it out, but usually I like it a little bit better and pull it out a little bit. Go back and tighten everything down.

Roush recommends against using an air impact for this part of the job. Use a hand tool or, like I said, I have a low torque impact gun, which is electric which will work fine. I'm going to repeat the process on the other side. All right, it fits great. Let's see how it sounds. It sounds killer. It's the same aggressive sound we got from the older Roush system. Sounds just as good on the 15.

Inside the car, the tone is very similar to the 11 through 14. It has that same kind of aggressive sound to it, but it's quieter. I actually don't think the exhaust is quieter. It's just that the 15 is actually much quieter inside so I think it's deadening a lot of the sound out. When you're at highway speeds, we're doing 65 right now, you can't even hear it. No drone, no nothing at all. You downshift, get on it though, it has that nice aggressive sound we're used to from Roush mufflers.

That Roush sound that was so popular with 11 through 14 is alive and well for the 15 too. It sounds nice and aggressive when you get on it, but on the highway it's real mild and no drone whatsoever. Installation is also pretty straightforward. Probably take you only around an hour. For the best selection of 2015 Mustang parts, make sure you check out For more install videos like this, make sure you subscribe to our YouTube channel.