Cam Benty
March 2, 2019

You’ve installed all the cool stuff like a supercharger, a big brake kit with six-piston brakes, aftermarket wheels, sticky tires and performance suspension pieces. But as with any build up, your vehicle is only as strong as its weakest link. In the case of our 2018 Mustang, that unfortunate description now fell to our factory driveshaft and axles, both of which were going to be hard pressed to deliver any form of long service due to the 600+ horsepower emanating from our 5.0-liter engine.

To help improve the durability of the driveshaft and axle systems, we headed once again to our qualified curator of Mustang enhancements, Sal Gutierrez, of Gear Driven Automotive for a simple yet essential upgrade of these two components. Gutierrez had recently completed the suspension and braking system upgrades on our Mustang so it seemed a natural progression to have him install the new GForce driveshaft and axles.

“A move to a stronger driveshaft is a good idea with engines over 600 horsepower from my experience,” noted Gutierrez. “There are certainly performance benefits to a single, lightweight driveshaft. The factory driveshaft is a two-piece shaft system with the Constant Velocity (CV) joint in the middle. It is this joint that is the biggest problem when used in a big horsepower application.”

Continued Gutierrez, “With regards to the axles, the GForce axles have a lot of advanced technology in the CV joint area and are beefier than the stock – all you have to do is look at them and you know they are far stronger than the factory counterpart. I’ve made the mistake of not upgrading to a performance axle and wished I had in the end.”

The GForce one-piece aluminum driveshaft we selected weighed in at 17 pounds, a full seventeen pounds lighter than the factory unit, and is rated to handle up to 900 engine horsepower and speeds of 160 mph. With a solid core, heavy duty U-Joints at both ends, you have a highly durable component. The new GForce driveshaft is 3.5-inches in diameter, meaning it is a direct replacement for the factory driveshaft with no vehicle modifications required.

As with all Ford Mustangs built since 2015, the independent rearend is a strong and versatile part of the S550 platform. Modern axles systems utilize CV joints to allow the rear wheels to act independently rather than the standard solid rearend used in Mustangs prior to 2015 (with the exception of some earlier Cobra SVT models). Because of this design, there are some weaknesses when big power is sent rearward. The GForce axles include severe duty CV joints, axles created with aircraft-grade alloys and one-piece, black e-coated inner and outer stubs. Powdercoated to protect against corrosion, they will retain their look for many years.

Machined from proprietary aerospace billet alloy, according to GForce, their Renegade axles are for modified cars with everything from mild performance upgrades to those with assorted power adder system that push the power way up. Featuring an upgraded 31-spline bar and 31-spline billet machined CV joints, they offer a huge improvement over the factory offering. In the case of our Vortech supercharged 2018 Mustang, they were the perfect step up axle.

The total change over from factory driveshaft and axles to the GForce components took about two hours total, of course we completed the job on a lift for ease of photography; we completed this simple swap with no real challenges. Follow along as we demonstrate the key element to this conversion that anyone with a modified vehicle should consider.

Parts List
GForce Engineering Renegade Axles
PN: FOR10107A
Features

  • Anti-wheel hop technology
  • Direct bolt-in fit and finish
  • 31-spline severe-duty CV’s
  • One-piece inner and outer stubs
  • Aircraft grade certified alloys
  • CNC-machined
  • Powdercoated axles for corrosion protection
  • Black e-coat finish on inner and outer stubs to protect against harsh conditions without impeding spline engagement
  GForce Engineering aluminum driveshaft PN: FOR10209A   Features
  • 3.5-inch aluminum driveshaft
  • 6061-T6 aluminum driveline tubing
  • Splined slip-shaft design
  • Solid core HD u-joints front & rear
  • CNC machined billet adapters front and rear
  • Bolt-in installation
  • Peak HP and torque increase
  • Reduced rotating mass

GForce supplied both the Renegade axles and aluminum driveshaft to increase the strength of the driveline system. Vehicle owners with over 600 horsepower should seriously consider upgrading these components to avoid catastrophic failure.
Before removing the driveshaft, place the transmission in neutral. On manual transmission cars this is obvious (if you are working on the ground, please chock the wheels so the car doesn’t move) and with automatic cars you can do this underneath by releasing the cover and shifting the cable to neutral.
Unbolt the rear connection of the driveshaft at the differential. These bolts are held in with Loctite from the factory so an impact wrench is required. In our case we had to step up to an air-powered impact – they were that tight!
After unbolting the four front bolts that hold the driveshaft to the back of the transmission, we needed a pry bar to gently unseat the U-Joint from the output shaft.
A similar technique was used at the back of the driveshaft although the “persuader” we used was much smaller.
Note that the driveshaft ends will swing down when the front and back ends are released. That is due to the fact that the factory center U-Joint bolts to the underside of the car. This is a key part of our driveshaft upgrade. This single factory U-Joint is unable to handle big power and will be replaced with a one-piece GForce driveshaft.
The GForce driveshaft front section is much stronger than the factory unit at the right for obvious reasons of larger U-Joint material and overall connection plate thickness.
The same holds true for the rear section of the driveshaft, the GForce on the left is much stronger than the factory unit. And note the very small nature of the factory driveshaft, which is down to about an inch overall at one point. The GForce unit measures 3.5-inches and is seven pounds lighter than the factory driveshaft.
The same holds true for the rear section of the driveshaft, the GForce on the left is much stronger than the factory unit. And note the very small nature of the factory driveshaft, which is down to about an inch overall at one point. The GForce unit measures 3.5-inches and is seven pounds lighter than the factory driveshaft.
After cleaning the surface of the pinion connection and the bolt holes, we test fit the new GForce adaptor; the fit was perfect with no alterations required.
We installed the hardware supplied in the kit and torqued the bolts to 50 ft-lb with a torque wrench as called out in the instructions.
This rubber “bellows” section back of the U-Joint will compress to allow the driveshaft to be pushed in place. This driveshaft was specifically for 2018 and newer Mustangs; GForce offers driveshafts for a wide variety of Mustang model years and other vehicle makes.
Installing a new one-piece driveshaft is fairly easy but having extra help will keep you from dragging the back end on the ground. Keeping U-Joints clear of debris is important to long term driveshaft durability.
After the driveshaft bolts are in place, torque them to 75 ft-lb to make sure they stay in place. Remember these bolts also received a drop of Loctite so they should not back out over time.
Next, we started in on the axle upgrade. After removing the rear tires, we inspected the brakes and pads along with other suspension components. To remove and replace the axles, the springs and shocks will not have to be removed.
First, we released the brake line clamp so that it would not be strained once the caliper was unbolted.
Next we removed the rear brakes, starting with the calipers and caliper housings.
Of critical importance is being careful as you removed the Anti Lock Brake sensor that fits to the back of the spindle. The ABS line is held in with one bolt at the end of the long cable shown here.
With the hold down bolt removed, gently wiggle the sensor out of the hole and tuck the cable away, making sure not to kink the line in any way.
We then removed the Baer EradiSpeed rotor to gain access to the spindle bolts. The rotor can become tight over time due to metal expansion so light tapping with a rubber mallet on the backside of the rotor may be required.
Remove the spindle bolts after providing a jack support under the spring. It is important to note that we are not removing the spring or shock. If you don’t support the spring, it could be released from its mount and that would be highly dangerous.
Remove the inner strut to help release pressure on the spindle. This suspension features a number of parts from a Steeda kit previously installed.
Using an impact gun, remove the center nut that attaches to the axle. An air impact gun many be needed to get this nut to release. Remove it completely.
Making sure not to drop the axle, remove the last bolts holding the spindle in place and the pull the spindle off the car.
Using a pry bar, gentle pressure the back of the axle at this point to release it from the rearend.
Once the axle is unseated, you might see differential fluid leaking down the outside of the case. Place a catch can under the drip to catch the fluid; the released fluid will not be reused and in our case, there was very little. Remember to refill the rearend when finished with the axle swap.
The GForce axles feature beefed up shaft material and high strength, severe duty CV joints. They are a direct replacement for the factory unit and snap right in place.
Slide the axle through the suspension components and into place. It is larger in size than the factory unit we just removed and will take patience to slide it past all of the other suspension components.
The splines on the new GForce axle match the factory unit but must be lined up with the original axle placement.
We did not use any tools to snap the new axle in place, just a fair amount of force by hand, pushing on the end of the axle from outside of the car. When completed, the axle system should be seated in position like this. From here, reassemble the parts you removed, noting the torque spec of the axle nut.

Photography by Cam Benty