Moses Ludel’s 4WD Mechanix Magazine – How-to: Chevrolet and GMC Truck AAM 11.5″ Axle Rebuild
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 guide.
The bump 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 pulling.
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 tooling.
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.