Always remove the fill plug first before the drain plug. If you drain it then can’t remove the fill plug for whatever reason, you’re screwed. And always fill by capacity, not till it comes out of the fill hole. If the vehicle isn’t level, or you’ve got most aftermarket diff covers you won’t put in the right amount by filling until it runs out.
The rear is much simpler- an enlarged bulb in the middle with 2 tubes going out to the 2 tires, almost completely hollow. The axle shafts go through the tubes and there is a lot of space between the shafts and the tubes. At the outside ends of the tubes there are bearings between the shaft and the tube, the bearing transfers the weight of the vehicle from the tube to the shaft, which then transfers it to the tire. Just outside of the bearing is a seal. The seal and bearing will be right behind the brakes meaning if the seal leaks you get lube on your brakes and your tires. Everything inside the axle from the seal on one end to the seal on the other end is exposed to the gear lube. Of course there is another seal where the pinion shaft comes out to connect to the driveshaft.
Do it your self, super easy. You can do both the front and back in 25 min
I had heard it was around $600 for both. I changed the fluid in both in a combined 37 minutes. I had never drained and filled a diff before in my life. I have a 2019 JLUR. I put in 75W-140 Severe Duty Synthetic Gear Lube from Amsoil. The rear diff took 25 minutes (first one) to drain and fill. The front took 12 minutes. I drove it around both left hand turns and right hand turns to ensure the fluid went everywhere internally it is supposed to go. I rechecked the levels and they were filled properly. It would take me more than 37 minutes to drive one-way to the dealer and I saved $550.
Be aware that not all cars have drain plugs, sometimes you have to pull the "pumpkin" partly out to drain the oil, and to do that you have to pull the wheels and tires and axles. On the fronts it's even more work depending on how the hubs come out. Worst case scenario, $600 still sounds on the high side to me but at inflated dealership hourly rates maybe that is what it would take. On a JL, barely more work than changing the engine oil.
I did my research on what it took to drain and fill the diffs on a JLUR and I was shocked at how easy it was. That is the only vehicle I have attempted it on, although as I have done all the maintenance on the Jeep I have started doing it on the other vehicles as well. So much easier than taking them in for simple stuff like oil changes and the like.
Sure have buddy. And every rear axle shaft has bearings on them which get lubed by the diff fluid. Every time I've pulled rears some diff fluid can/will leak out the end of the axle tube, which is why I'll jack that side up.
They are not flooded axle tubes though, the diff has seals at the gear/axle splined end, they should not be filled. If the axle tubes were flooded it would hold a gallon or more of fluid.
Depends on which bearing you’re referring to. The bearing at the wheel end on the axle is but lubed by diff fluid. The inner axle seals are on the outside face of the diff bearings, which are lubricated by the diff fluid.
Man, it's like talking to my kid.......I had stated the axle shaft bearings (which are at the end of the axle near the wheel) are lubed by the diff fluid. Anyone who knows anything about rear axles knows absolutely what I'm talking about. And of course the carrier bearings are lubed by the diff fluid. Lets agree that all of the bearings in the rear axle and on the rear axleshafts near the wheel are lubricated by the same fluid, which is the fluid in the differential. And that there's only one source of lubrication in the rear axle.....which is the differential fluid.
Huh? All of the bearings in a rear axle are lubricated by the gear oil contained inside the axle. Why does it matter which bearing it is?
