Catastrophic damage to GM aluminum front housings is being researched by the Differential Division at Jasper Engines & Transmissions. Many of the cores from 2002-2006 GMC Trailblazer and Chevrolet Equinox SUVs are sent to JASPER with either cracked housings or holes blown out the side
(see figure 1).
“Several things could come into play with these premature failures,” says Wayne Mehringer, JASPER Differential Division Manager. One such issue is failure of the outer pinion bearing. “The bearings in these units are very small and cannot stand any sideward or abnormal pressure,” says Mehringer.
Another issue could involve the transfer case. “Problems either with a viscous coupler, or the internal gearing, can put extreme pressure on the drivetrain,” says Mehringer. “This extreme pressure can make the outer pinion bearing heat up and fail.”
Issues with tire circumference can also cause differential housing failure, especially with all-wheel drive vehicles. “If one of the tires on the vehicle measures larger, or smaller, than the other three, this puts extreme pressure on the outer pinion bearing,” says Mehringer. “The bearing will eventually heat up and come through the side of the housing.
During the remanufacturing process, JASPER utilizes a retaining compound to help keep the outer pinion bearing from spinning within the aluminum housing (see figure 2). “JASPER will also use new ring and pinion gear sets, pinion bearings, differential case bearings, axle shaft bearings, a collapsible spacer, thrust washers, pinion seal and axle shaft seals,” added Mehringer.
May 10th, 2010 at 12:11 pm
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