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In the December, 2011 issue, we discussed the known weakness of late model Hemi axles. For unmodified or lightly modified cars on street tires, it’s not really an issue. But bolt on a power adder, change to some sticky drag radials or slicks, and the stock axles are living on borrowed time. Since we’re doing all of that to the Maulin’ Magnum, a call was made to The Driveshaft Shop and the driveshaft doctor prescribed some 1,400 hp rated axles for us (part number CH56).
Another weakness (at least for non-SRT Challengers) is the lack of a real limited slip differential (LSD). Stock, the LX/LC platform cars use the traction control computer and the rear brakes as an external limited slip device. This works for most cars under most conditions, but not so well for high horsepower cars and most definitely not at the drag strip. This time the urgent care call went to OS Giken (pronounced “O-S Geek-in”), and the automotive pharmacy dispensed one of their very stout and unique LSD units.
And finally we needed to upgrade the ring and pinion to a steeper (higher numerically) gear set. While the calculator showed that a 3.93 or so gear set would be best for the track, we actually drive the Maulin’ Magnum daily on the street. Richmond Gears makes a 3.55 gear set for our car that was just what the doctor ordered for a street/strip LX car. To pull all of this together and show us how to install the parts, we turned to the specialists at Unitrax Drivetrain in Anaheim, CA. With over 34,000 differentials set up since their founding by Jerry King 27 years ago, they know what they’re doing. For details on these parts and companies, see the December, 2011 issue.
With parts in hand, we pulled into a service bay at Unitrax ready to document the Achilles heel surgery. Our technician, Jose started pulling the rear axles out.