How-to: AAM 11.5" GM Axle Rebuild and
Ring-and-Pinion Gear Change
American Axle & Manufacturing ("AAM") builds OEM axles for Chevrolet and GMC
trucks and Dodge Ram. The magazine's own '05 Ram 3500 4WD came with an AAM 11.5" rear axle and an AAM 9.25" front
axle. The streaming rental now available from Vimeo On Demand covers the steps involved in changing
to a 4.56:1 axle ratio. The work applies to both GM and Dodge Ram AAM 11.5" axle assemblies. Note
that differentials and brake assemblies may vary. However, the overall axle and differential service
procedures remain largely the same and even include the 10.5" AAM axle design. When performing work on your
specific truck, use a factory shop manual as your reference
to 35" diameter tires left our Dodge Ram 3500's original 3.73:1 axle gears lacking. Too tall gearing for the
new BFG tires, plus an added 1,100 pounds of utility accessories during the Ram's
"makeover", the truck needed remedy. Boosting engine power was a possible solution.
A change to 4.56:1 ring-and-pinion sets
made better sense for our planned trailer
AAM axle gearsets are available from several sources, including American
Axle & Manufacturing. In 2012, we turned to Superior Axle & Gear for a quality "kit"
approach. Their package consisted of two ring-and-pinion matching sets (11.5" for the rear, 9.25" for the front)
plus Timken bearing sets, new ring gear bolts, preload shims, crush sleeves, seals, sealants, thread locker, tooth
contact paint, and a pinion nut for each set—complete!
Note: If you
cannot access Superior Axle & Gear products, consider using genuine AAM parts, they are the manufacturer of OEM
axles and replacement components.
For those familiar with Dana integral axles, the AAM approach is a
departure, especially the differential carrier removal and installation. In some ways, the AAM is quicker to set up
than the Dana units. However, like every axle type, the critical, adjustments remain the same and in this
sequence: 1) pinion depth into the housing, 2) pinion bearing preload, 3) differential/ring gear backlash, and 4)
carrier bearing preload.
The right tools are an important part of an axle build.
The AAM units require some specialty tools. In the Vimeo On Demand streaming rental's step-by-step coverage of
the ring-and-pinion gearset change, tools play an important part. Some tools are
inexpensive, others can be
improvised—a few will require willingness to invest in
Determine whether rebuilding your own
axles matches your skill level and tool budget. Whether this is a one-time task or your professional
work, the steps described in the Vimeo On Demand HD video instructional
rental will serve as a guide for these
critical tasks. The instructional level is also well suited for adult education Automotive Technology
classroom curriculum and training.
Skill level required: Familiarity with gear mechanisms and ability to follow technical
Needed tooling: Specialty tools required—consider the cost before taking on this kind of project. The
video describes a number of alternatives to expensive tooling and