Using a straight edge from...
Using a straight edge from the end of the 8 3/4, we measured the distance from the center of the pinion yoke to the ruler. This measurement was then transferred to the Dana 60.
Of course, aftermarket axles are recommended, and actually a requirement for us since we plan on racing this car on a regular basis, so we called the guys at Randy's Ring & Pinion for a set of hefty Yukon Units. Since our truck rear had an open differential and undesirable gear ratio, we also had the guys at Randy's set us up with a limited-slip unit and a set of 4.88s for hard launches. We considered a spool, but since this is a street car, the all-around drivability of a Sure Grip made more sense. A bearing and shim kit and high-performance pinion yoke completed our order from Randy's, and we were ready to begin fabricating our housing.
Narrowing a rearend housing, while evoking thoughts of complicated geometry and mathematics, is actually easier than you think. The tooling consists of a large piece of solid bar stock and three aluminum discs. Since we're cheap, and because our friend Lonnie over at Harrell's Automotive already had the tool, we just borrowed it from him. After cutting the ends of the truck housing to length, two of the aluminum discs are bolted where the carrier bearing races would go. The bar is then inserted, and the third disc fits into the Mopar axle tube end, keeping it square as it's welded in place.
We measured the total width...
We measured the total width to obtain the length of the other axle tube. This will be used when one end is welded to the Dana housing. By measuring in this manner, the offset of the pinion yoke will be correct.
The only problem we encountered was when Associate Editor Kevin "Hacksaw" Shaw inadvertently cut one of our axle tubes too short. While this did suck, it was quickly remedied by ordering a length of axle tubing from Randy's Ring & Pinion and welding it in place. Lesson? Measure twice, cut once!
After measuring and welding our new housing together, it was time to set up the Dana 60 with new bearings, gears, and our Sure Grip differential. If you've never set up a set of gears before, our recommendation is to get help from someone who has. Since improperly installing any of the components in a rear differential can lead to accelerated wear, noise, or, worse yet, catastrophic failure, we enlisted the help of friend Tod Struck at Inline Performance Specialist. Tod's company specializes in heavy-truck maintenance, so he is familiar with the procedures and has all the tools necessary to properly set up a Dana 60. In a short time, Tod had our Dana assembled and ready to install with all our fresh internals. This rear should easily handle the abuse we'll give it and should be the last rearend we ever put in our Charger.
Now if we just had a motor in our project car, we'd head to the track for some testing.
We cut the first axle tube...
We cut the first axle tube using a Sawz-all with a metal cutting blade. An industrial metal bandsaw would have been nice, but we didn't have one so we made do.
Using a grinder, we chamfered...
Using a grinder, we chamfered the edge of the axle tube where the new end will be welded on. This will ensure a solid weld at the tube end.
With the first axle tube cut...
With the first axle tube cut to length, we installed the two aluminum bushings of the narrowing tool where the carrier bearings go and torqued the caps.
The third bushing fits into...
The third bushing fits into the new axle tube end and then slides onto the metal bar that is held in location by the two carrier bearing bushings. This ensures the tube end stays properly aligned while it's being welded.
Since the position of the...
Since the position of the tube ends also determines the position of the brake backing plates, we used a carpenter's square to align them properly with the rearend housing.
The end can now be welded...
The end can now be welded to the axle tube. Making short welds opposite each other will ensure the parts are evenly heated and don't distort during welding. This step is then repeated on the opposite axle tube, and the housing is complete.