Ford 9 Inch Rear End - Tuff as Nails!

Moser Builds a Hefty New 9-Inch

By Grant Peterson

The 9-inch Ford rearend has been the standard all-around bulletproof rear gear for years-in fact it's been the leader since its introduction in 1957. Back in the day, the big Olds rearends were found in many high-horsepower drag cars and things, but they too had to endure some mods to hold up and plenty were still blown up. Withstanding that brief period of competition, the 9-inch has always found a home under the frames of countless hot rods, trucks, customs, musclecars, and not to mention all the production line cars and trucks from Ford that were born with them.

To accommodate the ever-growing numbers of these vehicles that still require the brute strength-and then some-of the old 9-inch, the enterprising folks in the aftermarket have stepped in. Because of this it's almost prohibitive to try and use and old unit to suit your needs. Today there are more variations and options available than ever before with many of them being a bolt-in to your custom application-just add oil!

Moser Engineering is one of the heavy hitters in the rearend game, and in the last 24 years has seen more than its fair share of axles. We are going to check out what goes into one of their new 9-inch rearends from start to finish-beginning with a glance inside a complete aluminum center section.

This center section in the build pictures is almost exactly the same as the one going in the Roadster Shop chassis that's waiting for a '58 Suburban body except that ours has a nodular iron case and the one shown at Moser has an all aluminum case that saves up to 14 pounds over the iron version. The iron case is heat-treated and stress relieved before any machining is done while its lighter brother consists of 356-T6 aluminum with 7075-T6 aluminum caps and billet steel adjusters and relies upon its super strong thru-bolt design to give the case increased strength and decreased ring gear deflection that's common in most other aluminum case designs. Basically-you can't go wrong with either one-it just depends on how much coin you have to invest.

In this story, we'll be using Moser's housing, axles, and third member, which will eliminate the possibility of parts not working together, evident in the smooth way in which the whole build transpires. After going through all the steps here, all that is really left is to break-in your new rearend. Moser recommends doing that as follows for street applications:

1. With the car still on jackstands and the rearend filled with proper amount of non-synthetic lube.
2. Run in forward and reverse for approximately 2 to 3 minutes.
3. Drive vehicle approximately 10 miles at normal operating speed including accelerating and slowing several times conservatively, then let your truck cool for one hour.

Remember to do all this as safely as possible, and you can always call Moser's tech line for help. After all of this, you'll know that your rearend won't be the weak link in your drivetrain.