Part 5: Strength And Durability For The Dana 30 Front Axle
We went over the buildup of our rear axle last month, so now it's time to cover our front axle buildup which was a bit more extensive. Custom Dana 44s and 60s are really nice, but out of our budget. Yeah, we would love to have them too, but we decided to go with something that the average guy could easily duplicate in his garage at home.
While our Grand came with a Dana 30 front end that has served us some 95,000 miles, we had only been using an open differential and 31-inch tires. With 33s, and possibly 35s in the future, we felt something stronger was in order. While Dana 30 is not ideal, a buddy gave us a high-pinion 30 out of a Cherokee XJ. The high-pinion gains us two things: the ring gear is being driven on the proper side, and we would have less front driveshaft angle with the pinion coming out the top of the housing instead of the bottom. For gears, we again went to Motive Gear, company that has a long history as an OEM supplier, as well as to the aftermarket and to full-on racing of all kinds. A set of 4.10:1 gears was our choice, which with 33s would be the same as our previous 3.73:1 gearset and 31-inchers, though now we wish we had gone to 4.56:1s.
We wanted to have something to drive them equally, and the logical choice was ARB's relatively new 30-spline Air Locker. One of our biggest hang-ups with the ARB unit in the past was the fact that you had to notch the carrier bearing cap for air line clearance. To us, this just wasn't right. Well, guess the engineers Down Under finally also figured this out, and found a way to route the air line without notching the cap. Plus, there have been some more engineering updates to improve the overall strength of the unit. It's tough to find a place to mount the necessary air pump to operate the Air Locker, but we finally discovered just the right amount of room next to our K&N air filter.
For axleshafts, the original booted CVs were not going to hack it with all the new traction we were developing, so in went a special set of Superior's 4130, 30-spline shafts that use the larger-style 297 U-joint. However, we still had to run the smallerdiameter outers to fit in the stock-sized unibearing hubs. These are also made from 4130 material, so we really don't expect any problems. We replaced our original unibearing hubs with a pair from Crown Automotive. We also installed new ball joints sourced from Crown in the steering knuckles. Definitely quality stuff from Crown, not some cheap off-shore knock-off. We have used a lot of Crown's products in the past and have been very pleased with the results. OK, you can't buy directly from Crown, but Quadratec is our supplier.
Speaking of ball joints, don't try to pound the ball joints in and out with a big hammer! Use the proper ball-joint press tools to do the job right. Our low-cost tool set came from Harbor Freight and works great.
With Superior's new larger-diameter 30- spline axles come new inner tube seals. The short side is a '03-'06 Jeep Rubicon seal, and the long-side tube is a National seal (PN 473210). However, on the disconnect axle, a seal seat was never machined on the long-side axletube within the housing, as oil sealing was done at the disconnect housing. This means that there is nothing to support the long-side inner seal or to keep it square within the tube. Chris Overacker of Code 4x4 (www. code4x4.com) shared with me a little trick. I machined a chunk of aluminum bar down to .0025 inch over the axletube inner diameter and pressed it into the axletube. Now, the seal can rest solid against this bar and there is no chance of knocking it out when installing the axleshaft. Oh yeah, there is a 1.40-inch hole in it with a tapered "ramp" for the axle to slide through.