The Jeep JK Front Axle Seal
by Marcus Trusty, Colorado Crew
This article is reprinted with permission from the author, originally posted at keeptrailsopen.org
Routine maintenance is an important thing for any Jeeper, but especially if your Jeep sees 50+ trails each year. Between trail patrols, recreation, stewardship projects and events, I put a lot of off-road miles on my JK last year. It’s important to keep everything in working order so your vehicle won’t let you down when you are in the middle of nowhere, coupled with the fact that this Jeep is also my daily driver, maintenance is of the highest priority.
Last summer I installed some high-strength chromoly axle shafts both front and rear in my JK. They came assembled and the swap was simple, or at least I thought it was. A few weeks later, I noticed some drops of oil in my driveway. I must have damaged one of the seals when I put in the new shafts. Now, I will begin this ordeal by confessing to being a little OCD about my vehicles leaking fluid. I can’t stand it, and it makes me go bananas when I have large oil stains on my driveway. My mind has a way of making me think all my neighbors and passers-by are judging me by the large oil stains clearly visible from the street. I’m crazy, I know.
I have messed with axles and differentials before, but I had never taken apart a Rubicon differential with the electric locker, wiring, and the sensor in the back of the diff housing. I watched a few videos and read a write-up or two and decided it wasn’t that big of a deal. I bought a cheap front axle seal and began to disassemble my front axle. I pulled everything apart, pulled the carrier out, knocked the seal out, found a big socket that somewhat fit the inside housing of the new seal and used it, along with several socket extensions, to pound the new seal in place. I reassembled the front axle and proceeded to be impressed with myself because the entire project took about 3 hours.
I had a Jeep event in Denver the next week and I was relieved to get the seal fixed before driving at highway speeds and not knowing how much gear oil was in my diff. I drove down to the event, arrived at our hotel and unloaded for the night. I come out the next morning to find a puddle of gear oil under my Jeep. I get down on my hands and knees…and, sure enough, it’s coming from the side of the axle I just changed the seal on. SOB! Now I’m just pissed because I didn’t see any oil all week and I had just taken the time to change the seal out with a new one. I survived the weekend and got home without the front diff blowing up from lack of oil. I immediately start reading threads about other JK owners having new seals fail and that several JKs are having similar front axle seal issues. After looking around a bit, I find a thread where a guy had used a Yukon Gear and Axle seal for a TJ and put it in the front of a JK. He had good luck and the seal worked perfectly. When I was looking at the Yukon site and their Diff Wizard, which is really helpful by the way, I noticed they had a nice seal install tool, and since I am also working on a one-ton swap in my YJ, I decided to get a seal tool. This tool will work on Dana 30, 44 and 60 front axles.
So here we go again, I finally get a day when I have about 3 hours and I put the Jeep on jack stands and start disassembling the breaks, unit bearings and remove the shafts. Next, I pulled the cover and drained the oil. To disconnect the locker wiring you need to first remove the bolt holding the plastic plug in the top of the axle, you can then pull the wiring up enough to disconnect the plug. Then, fish the end down into the diff and pull the carrier out. Now you will be able to see the inner seals and the locker sensor in the back of the diff.
I removed the seal by sliding my jack handle into the axle tube and tapping the seal out. Make sure to also clean your tubes out so residual gear oil doesn’t leak out making you think the seal is leaking again.
Once the seal is out, position the new seal in the axle tube, then use the seal install tool to hold it in the right location. One side of the seal tool will sit against the opposite side of the diff housing and a threaded shaft will connect it to the seal driver. Tighten the nut up by hand to get enough pressure for the tool to hold the seal in the correct spot. Then, slowly tighten the nut with a wrench until the seal is fully seated. No joke, this took all of 20 seconds to install the new seal with this tool.
Now you can start putting everything back together. I read a write up on how to correctly setup the Rubicon locker sensor to work before putting everything back together. The plunger on the sensor gets pulled out when the locker engages so it’s important to pull it out, hold it, and then install your carrier. To do this, I cut a short piece of toothpick to hold the sensor plunger out. I tied some fishing line around the toothpick and let it hang loose in the diff. I installed the carrier and then pulled the fishing line releasing the toothpick and allowing the plunger to retract into the correct position.
I reassembled the entire axle, filled it with gear oil and proceeded to drive around the next two weeks, checking several times a day to see if there was gear oil coming from the axle tube. I am happy to report that the Yukon TJ seal worked, and my driveway is still clean! Thank you to Yukon Gear and Axle for their quality parts, tools, and for helping us keep our equipment in good condition. Now, off to my next project.
Front Seal, Yukon Part # – YMSC1003
Seal Tool, Yukon Part # – YT SA-01