There comes a time when you simply know your axle is too weak for the tires you are running. That time came for us while prepping the Mega Titan for a trip to Central California's Pismo State Beach for some sand-dune running. Like we always do before a trip, we popped the differential covers of both Pro Rock 60 axlehousings to inspect the gears for chips or other signs of damage. We'd noticed a slight ticking sound as the guys at Triple-X Traction spun the tires with the truck on jackstands. At this point, we were forced to admit that we had some type of issue. Once opened up, the oil drained out to reveal several broken teeth on the pinion gear in the rearend. Much to our dismay, this meant our 4.56:1 gearing was not going to survive against 46-inch tires and 400 hp. Additional beef was in order. So we phoned Dynatrac to see what they thought of our problem.
At first Dynatrac's technician thought we were joking about damaging a 4.56:1 Dana 60 pinion gear with just 400 hp; then we dropped the 46-inch-tire surprise on them. The conversation quickly led to a discussion about how we used the vehicle. As soon as the words "crushing cars" and "30-minute burn-out" were announced, the technician told us our only option was the Pro 80. The idea that we could step up to a Dana 80 to solve our issues made us giggle. Not only would a completely new axle assembly allow us to fix a potentially weak link on the vehicle, but it would also enable us to convert the 20-plus-foot long Mega Titan to rear steer. Follow along as we showcase the buildup of the ultimate Dana axle.
1. This is where a Pro Dana 80 axle begins life. The nodular-iron centersection is machined to exact tolerances. We weighed our unit just to see to how heavy it was. We weren't surprised to find out the completed centersection weighed 122 pounds by itself. That's almost 40 pounds more than a Pro Rock 60 centersection. The big difference between the two, aside from the overall size, is the webbing thickness. The increased webbing adds significantly to the rigidity of the larger centersection.
2. Here you can see the physical difference between the actual axletubes of a Dana 60 and 80 axle by Dynatrac. The Dana 60 tubing is 31/8 inches in diameter and 1/2 inch thick, while the larger Dana 80 tubes are 3 5/8 inches in diameter and 9/16 inch thick. This added strength should enable the Mega Titan's new rearend to survive a considerable beating without issue.
3. Step 2 in the process was...
3. Step 2 in the process was to press the inner Cs onto the axletubes.
4. With the inner Cs pressed...
4. With the inner Cs pressed in place, the next step was to weld the Cs in place.
5. Check out the sweet welds...
5. Check out the sweet welds the Dynatrac technician laid down. Part of his secret for this is the rotational jig that slowly rotates the tube as it is welded.
6. We had these lower link brackets made prior to our appointment with Dynatrac. Twisted Metal Fabrication of Sacramento cut these from 3/8-inch steel sheet material. We did this so that the brackets could be installed on the axletubes prior to them being installed in the centersection. That way, the brackets could totally encompass the tubes, adding significant strength to the lower link mounts.
7. Here you can see the new...
7. Here you can see the new Yukon 5.13:1 gearset (Dude, it's about time!-Ed.) fitted to the new ARB Air Locker sourced for the project.
8. The next step of the assembly...
8. The next step of the assembly process was pressing the axletubes into the centersection. Once pressed in place, the technician performed a series of rosette welds to secure the centersection to the axletubes.
9. After the housing cooled...
9. After the housing cooled down, it was moved to a cleaning area where it was scrubbed down to ensure it was free of debris. Once dry, the exterior was given a thick coating of black enamel paint to protect it from rusting. Next, the assembly technician started the process of setting up the ring-and-pinion. Once the gears were set up properly, the ARB Air Locker was bench-tested for proper operation.