Ford 9-inch Rear Axle | 31-Spline | 78-79 Ford Bronco, 73-79 F150 SKU: 798606NET

Ford 9-inch Rear Axle | 31-Spline | 78-79 Ford Bronco, 73-79 F150

Product Overview:

When you’re running big tires and putting power to the ground, stock axles won’t cut it for long. The Black Forge™ 31-Spline Rear Axle for the 1978–79 Ford Bronco and 1973–79 F-150 4x4 is built from high-strength 1541-H alloy to handle serious trail use. Finished in black oxide for added toughness and corrosion resistance, this fully assembled 32" axle is ready to drop into your stock 31-spline Ford 9-inch setup and get to work.

Full description

Black Forge™ 31-spline Rear Axle for Ford 9" | 78–79 Bronco & 73–79 F-150

If you’re running bigger tires and putting serious torque through your drivetrain, this Black Forge™ 31-Spline Rear Axle for 1978–79 Ford Bronco and 1973–79 F-150 4x4 is built to take it. Constructed from 1541-H alloy steel with a black oxide finish, this axle is designed to handle the added load and hard use of off-roading and high-traction setups. At 32" overall length, it fits either side and comes fully assembled.

1541-H alloy steel construction: Superior strength for high-torque and off-road applications
31-spline shaft: Fits right into the factory 31-spline Ford 9-inch rear end for a clean install
Black oxide finish: Resists corrosion and adds surface hardness for long-term durability
Tapered roller bearing design: Handles increased side loading from oversized tires and aggressive driving
Fully assembled: Ready to install out of the box—no pressing or setup required

Additional Info

Fitment: 1978–79 Ford Bronco; 1973–79 F-150 4x4 (right or left side)
Overall Length: 32"
Retainer Hole Size:
- 1973–1978: 1/2"
- 1979: 3/8"
Spline Count: 31-spline (Ford 9-inch)

Built from 1541H alloy with a black oxide finish, this axle delivers serious strength for off-road rigs and high-powered a 78-79 Bronco or 73-79 F150 4WD truck.

California residents: Proposition 65 Warning

Questions & Answers

PRODUCT REVIEWS

Blaine Scully

Reviewed 01/28/2026

I twisted my stock 31 spline axle shaft in half, while I was going up a Rock Trail climb of sorts. I then went ahead and ordered the upgraded Wild Horses 31 spline axle shaft for the one that I broke and for the other side so it was matching. That was one of the best decisions I've made this far on adding to my Bronco. Since then I have gone rock climbing and other various types of intense Terrain with almost 500 foot pounds of torque backing It Up On 6 in of lift and 35 inch tires. These axle shafts not only hold up amazing but they look great too. What made this whole experience even better was the customer service that I experienced while purchasing this. I originally only ordered just one to replace the broken axle shaft while I was still on the mountain waiting to get trailered off of it. It so happened to be New Year's Eve about 10 minutes before midnight. After ordering it I realized that it wouldn't be wise on my part to have one stock axle shaft and one upgraded one so I ordered a second one afterwards with a car cover for my 66 Bronco. I then received a call the following Monday from Wild Horses asking if I had meant to make a double order of the same axle shaft on accident, being that it was New Year's Eve after all. And I confirmed that that's what I wanted to do and therefore he helped reduce my shipping costs and also adding the promotional code discount that wasn't letting me apply during checkout online. Wild horses now has a customer for life because I will always have a Bronco as far as I am concerned. Definitely recommend!!!

Marcos

Reviewed 08/06/2025

They fit great, they look pleanty strong however the best part of the transaction was the customer service. I had technical issues that were cleared up by the staff. Im horrible at remembering names but both dudes Intalked to were super friendly and knowledgeable!

T K

Reviewed 08/14/2011

The axle I ordered came in fully assembled and ready to install. It worked perfect and was very reasonably priced. I checked other sites and found this to be the best overall deal.