Yukon Gear Dana 44 JK Rubicon Replacement Rear Pinion Seal
Gear oil slung across the underside of the fuel tank, a wet ring around the rear driveshaft yoke, or a rear axle that takes more oil than it should at every service are the classic signs of a leaking pinion seal on a Jeep Wrangler JK Rubicon. Yukon part YMS54458 is the replacement rear pinion seal for the Dana 44 used under 2007-2018 JK Rubicons, and it is a single seal sold on its own for the owner or shop that only needs to stop the leak.
The pinion shaft exits the front of the differential housing and carries the yoke that the rear driveshaft bolts to. The pinion seal is pressed into the housing bore around that yoke and rides on the yoke's sealing surface, keeping the gear oil in and keeping water, mud and grit out of the pinion bearings. On a Rubicon that sees water crossings and lifts that change driveshaft angle, that seal and the yoke surface take more abuse than on a stock street Jeep, and once it weeps, the outer pinion bearing is the first thing to run low on oil.
Clean the front of the housing and the yoke, drive a few miles, and look again. Fresh oil coming from between the yoke and the housing is the seal; oil running down from above can be a cover gasket or vent, and oil at the wheel ends is an axle seal, which on a JK is handled by the JK rear axle bearing and seal kit instead. Grab the yoke and try to move it up and down. Any noticeable play means the pinion bearings are worn and a seal alone will not stay dry, and the axle needs bearings. Our Jeep Wrangler JK and JL service guide covers fluid service intervals for the rest of the driveline.
YMS54458 is cataloged by Yukon resellers for the rear Dana 44 under 2007-2018 Jeep Wrangler JK Rubicon and Unlimited Rubicon models. Some catalogs also list it for the 2007-only JK Dana 35 rear with a 24-spline pinion and for the JL Dana 35 / 200mm rear, while separate parts are sold for the JL Dana 44, so do not assume it fits every Wrangler rear axle. Confirm you have the Rubicon Dana 44 (axle tag on the tube, or the build sheet), compare the old seal's diameter and lip if you can, or send us the year and VIN before ordering.
Mark the driveshaft to the yoke and unbolt it. Before touching the pinion nut, measure the rotating torque of the pinion with an inch-pound torque wrench and mark the nut, shaft and yoke. The JK rear Dana 44 pinion uses a collapsible crush sleeve, so when the nut goes back on you tighten it only until that original preload is restored. Overtightening crushes the sleeve further and burns up the pinion bearings; backing off a loose nut does not undo it. Pull the yoke, check its sealing surface for a groove (a grooved yoke will chew up the new lip), pry out the old seal without scratching the bore, and drive the new one in square with a seal driver. Refill to the bottom of the fill hole with the gear oil weight your owner's manual lists for the rear axle.
If the pinion had play or the axle is already whining, do the job once: the Dana 44 JK rear master bearing kit includes pinion bearings, crush sleeve, nut and gasket, and a regear for bigger tires is covered by the JK Rubicon Dana 44 rear ring and pinion install kit.
| Brand | Yukon Gear & Axle |
| Part number | YMS54458 |
| Fits | Yukon Gear Dana 44 JK Rubicon Replacement Rear Pinion Seal |
| Type | Differential Seal Kits |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
This seal is cataloged for the JK Rubicon rear Dana 44, and some catalogs add the 2007-only JK Dana 35 with a 24-spline pinion. Non-Rubicon JKs used different rear axles depending on year and package, so read the axle tag or send us your year and VIN and we will confirm before you order.
No. YMS54458 is the pinion seal only. If you need a new crush sleeve and nut, for example because the pinion bearings are worn, use a JK rear Dana 44 master bearing kit.
Not on a crush sleeve pinion. Measure the pinion rotating torque before removing the nut, mark the nut position, and on reassembly tighten only until the original preload returns. Overtightening crushes the sleeve and overloads the bearings.
The usual causes are a grooved yoke sealing surface, a seal driven in crooked, worn pinion bearings letting the yoke wobble, or a plugged axle vent pressurizing the housing. Check all four before replacing the seal a second time.
Retail installers rate it about 2 to 4 hours, mostly in the driveshaft removal, preload measurement and careful nut reinstallation.
