For your average truck owner, the factory drivetrain parts and traction-aiding differential options are more than enough. But what if you’re not the average user? Let’s say you take your truck to work every day. Notice that we didn’t say you drive it to the office every day.
| 1104dp Increased Torque Capacity For Gm And Dodge Aam Rear Axles removing Yukon Axle
This article is for guys who use their trucks like the workhorses they were meant to be. Hauling concrete, lugging around pallets of building supplies, and towing trailers loaded with equipment demands more of a truck in a week than commuting to the office could in a truck’s entire life span.
Toss in the fact that during your off time you tow a toy hauler, do some weekend drag racing, or even hook to the sledand you, my friend, are far above average!
| Stock, 30-spline shaft(top) Yukon, 38-spline shaft(bottom) The new Yukon 38-spline axles for the Dodge AAM 1150 axles are made from a better steel alloy (G43400 vs. H15410 for the stock axles). The case-hardening depth is more than 43 percent deeper than stock. Most important of all is the fact that the minor diameter of the splines is virtually the same as the major diameter of the stock axle.
If you’re smiling and thinking, That’s so me, then you’ll appreciate this 38-spline axleshaft upgrade for the ’01 to ’10 GM and ’03 to ’11 Dodge AAM 1150 rear axles from Yukon Gear & Axle. This kit replaces your stock 30-spline full- floating rear axleshafts with larger and much stronger shafts. The OEM axleshafts for the AAM 1150 on the Dodge are manufactured with reasonably good steel. We say reasonably good because everything on an OEM level is a compromise between durability and cost. It’s the old tug-of-war between the accounting and engineering departments. Yukon Gear & Axle uses a superior grade of steel for its replacement axles and takes it one step further for the 38-spline upgrade axles.
How Much Stronger Are They?
Made from G43400 steel, the Yukon 38-spline axles for the AAM 1150 (also known as an 11-inch ring gear 14-bolt) rear axle are larger in diameter than stock (1.625 inch vs. 1.550 inch). This doesn’t seem like much at first glance, but looking closer we see that the minor diameter of the 38-spline shafts are virtually the same as the major diameter of the stock shafts. The bottom line is the superior alloy, deeper case hardening, and larger-diameter shaft result in an axle that is approximately 45 percent stronger than the stock piece, according to Yukon.
The second half of the 38-spline axle upgrade is the Yukon Grizzly locker. The Grizzly is an automatic locking differential, and as such doesn’t require input from an outside source to engage. This means it works without the driver having to hit a switch or pull a cable, and traction is available when needed, without thinking about it. Unlike a spool, a Grizzly locker can unlock when cornering and provides a smoother and tighter turning radius. This also reduces tire wear and allows for better handling.
| Here you can see a stock axleshaft (left) compared to a Yukon 38-spline upgrade shaft (right).
Installation of the Yukon 38-spline axle kit is almost as simple as a gear upgrade. The only difference is the boring of the spindles to allow the larger diameter axleshafts to be used. Teardown, spindle boring, locker install, and gear setup can easily be done in less than a day. While changing gear ratios is an option, it is not required. Once installed, you will have the peace of mind that comes with knowing you have the toughest rear axles available for your truck, and the increased traction of a locker to keep you going in the toughest of conditions.
Tips From The Pros
With your new Grizzly locker and 38-spline axles in place, it’s time to install the cover and fill the diff. Remember, if you’ve installed new gears you will need to gently break them in for about 500 miles. This means no towing, sled pulling, or drag racing. Failure to break in a new gear set can result in premature failure. After the break-in process is over, be sure to drain the oil and replace it with a premium synthetic or semi-synthetic gear lube. Note, our test truck was previously upgraded to a high-capacity cover from ATS. Increased oil volume means cooler operating temperatures and longer life.
| 1104dp Increased Torque Capacity For Gm And Dodge Aam Rear Axles diff Cover Install
