10 Bolt Yukon axles and a Detroit C-Locker

To continue our three part series, we now move to the rear of our project Blazer. To refresh everyone’s memory, while doing some suspension measurements on a new lift kit we installed, we had located our Blazer on the side of a hill. This is where we were when unpleasantly introduced to the sound of not only one axle exploding in the front of our truck, but also the left rear axle wanting to exit the housing as well. Of course, as you are probably familiar, this particular differential has “C” clips that hold the axles into the side gears of the carrier. So, not only did we have the problem of dealing with the broken axle, but also with the axle sliding out of the housing as the truck moved. We were now forced to figure out just how we would get our Blazer home. Luckily, several friends were with us that day, and we all put our heads together and figured it out.

As you can see in the photos, we used a pair of heavy ratcheting straps, and looped them around the wheel/tire and then around the backing plate for the rear brake shoes to hold the axle into place. This worked for a little while until we hit the pavement. Here we decided to pull the brake drum off and attach the wheel to the axle only. This kept the axle from wanting to “walk” out and after a five-hour ordeal, we finally made it home.

Now, this leads us to the next decision. What are we going to replace our stock 28-spline axles with?

How can we upgrade them so that we won’t run into this problem again? It was decided that we contact our good friend Randy Lyman from Randy’s Ring and Pinion Service in Everett, WA. When we told him of our misfortune, he wasn’t all that surprised. The stock 28-spline axles are notorious for breaking at the taper near the splines, as were the front axles. Once we removed the broken axle, we inspected our lock right locker for any damage and none was found. The carrier though had some areas of concern. Where the side gears of the lock right fit into the carrier, there was a small amount of slop. This wasn’t a big surprise seeing that it had a 100,000 miles on it and we wheeled it pretty hard for three years. Randy took all of this into consideration and made the recommendation for us.

Knowing that the 28-spline axles are not the strongest answer, we decided to go with Randy’s new Yukon line of axles. We ordered a pair of his 30-spline chrome-moly axles and, to take care of the sloppy carrier problem, we also ordered the latest version of Detroit’s “C” locker. This was a huge upgrade because this will replace the weak stock carrier with a much more durable unit that is a complete replacement for the carrier and has the locker incorporated into it. Even though our “drop-in locker” has been absolutely trouble free for three years, the added strength of a Detroit locker is a big relief for us. Coupled with the Yukon chrome-moly axles, we think that this combination should service us well for many years. As with any axle or ring and pinion order from Randy, he spares nothing. He supplies everything needed to do the job the right way. All seals needed for this job as well as Timken bearings and lock tight are sent along with every order.

Now comes the install. We will be the first to say this was more than we wanted to tackle. If it were just replacing axles, we would have been comfortable doing it. Seeing that the ring and pinion would need to be set up again for the proper coast and drag due to the new Detroit, we called upon Tucson Differential and Jay Sinclair. Jay was happy to help us with our new axle and locker project and took us slowly through the install process and explained each step of the way. 

The first step after we arrived at Jay’s shop (Tucson Differential) was to rack up our Blazer and have better access to the rear differential. Jay has manufactured nifty carts that roll under the truck, have a self-contained oil collection system and racks for all of the tools needed to do the job.

After the cover bolts are loosened and removed, it’s time to remove the carrier and the weak components. First we removed the “drop in” locker that we originally had and then removed the “C” clips that hold the weak, stock axles in place. With the axles free, carefully slide them out of the axle tubes. Now, remove the carrier itself and this is accomplished by removing the bolts that hold the bearing caps over the carrier. Some “persuasion” may be necessary to remove your carrier and a pry bar may be needed to apply pressure while the carrier is rotated slightly. With our housing now empty, we inspected the differential carrier and the inner axle tubes for debris. It’s now time to move over to the workbench to start mating the new Detroit C Locker to the ring gear.

Once the stock carrier is on the bench, its time to remove the ring gear from the original carrier housing. Jay carefully uses a chisel to help the ring gear separate from the carrier. After the ring gear is off, Jay prepares the locker and the ring gear to mate with one another by taking the time to hand file the surface of each to ensure a perfect fit. Jay stressed that this is an important practice that is often overlooked and can lead to premature failure. Once prepped, Jay moved onto installing the ring gear onto the locker. When installing the ring gear bolts into the locker, Jay always uses lock-tite to ensure that the bolts don’t come loose and uses the proper toque sequences to prevent bolt stressing.

  Installation:

Moving over to the press, it’s now time to install the new carrier bearings that Randy includes with his Detroit. After the new bearings are pressed on, the tedious part of the upgrade begins. NOTE: A press should be used whenever installing any “caged” bearings. Further, you should always make sure that your bearing is seating square and there should be no gap between the seat of the bearing and the item you are pressing the bearing onto.

Now that the ring gear is installed onto the locker, it’s time to put it back into the differential housing to set the proper coast and drag setting. Now come the critical steps of placing the exact shims between the ring gear/locker assembly and the differential housing. Jay first starts with a general idea, then installs the bearing caps that hold the locker in place and uses a dial indicator to achieve a starting point. After recording the first set of measurements, its time to pull the Detroit back out of the differential. Now, we headed to the wall of shims. Wow! So many to choose from, but Jay narrowed the choices and pulled a stack off the hook and starts to measure one by one to find a matching pair. This again is a critical step because the life and longevity of the ring and pinion rests on the proper selection of shims, which is also the controlling factor of coast and drag. After installing and removing the carrier assembly, Jay got our settings perfect and the Detroit is now installed. The carrier bearing caps are torqued to manufacturer specs and the Detroit locker is now at home in our ten-bolt housing.
NOTE: Be sure to mark the top and the left/right side of each bearing cap.

Now that the Detroit is finished, its time to prep our new super-stout, 30-spline, chrome moly Yukon Axles from Randy’s Ring and Pinion. One more trip to the press was required to install the new studs into the Yukon axles. After the studs were in, we moved back over to the Blazer and installed the new axle seals supplied by Randy’s Ring and Pinion Service. To keep from damaging the new seals, Jay uses a special seal seating tool. Once completed, its time to slide the new Yukon axles carefully into the differential housing tubes and line up the splines in the Detroit with the splines on the axles. The “C” clips are now reinstalled on the end of each axle, and the cap to the Detroit is installed with its retaining bolt. We finished by installing the differential cover with new gasket from GM, and filled the housing to the proper level with fresh gear oil.

The total time of this install took less than 2 1/2 hours thanks in part by the quality products provided b Tractech, Randy’s Ring and Pinion Service and the quality service provided by Tucson Differential.
Jay took his time to explain the entire process to us and we now have a greater appreciation of what skill is actually needed to do this job. As a footnote, Jay installed the gears that are in our Blazer 30,000 miles ago. When he removed the cover, I was amazed at how perfect the wear was on the ring gear and the condition of our drop in locker. This is a testament to the quality of work that Tucson Differential provides to all of their customers.