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My C7 (2015 M7 base, non-Z51) has sprung a leak from the rear axle shaft seals. Driver's side leak is definitely more pronounced than the passenger side.
Just curious what's involved with replacing these seals and whether it's a DIY type of repair.
If I were to have a shop do it, what's the book time per side?
You have to pull the axle shafts. Then you remove the old seal and install the new one. A shop is probably going to tell you around 2-3 hours per side.
Pretty rare for these seals to leak. Usually the rubber boots on the axles tear. Even though they're packed with grease, they will spray some liquid out of them.
"DIY" depends on your skill level. I needed to change an axle. The below gives you an idea of what to expect.
As previous poster said it is unusual for seals to leak. The differential has a vent on it to prevent pressure build up, be sure to check the vent & make sure it is not stopped up, as a stopped up vent can cause the axle seals to leak.
Thank you for your responses and sharing the photos. I checked the fluid and it's definitely gear oil.
It looks like axle removal is pretty straight forward. On some of the previous cars I have had, the axles were locked inside by a circlip, necessitating removal of the entire differential assembly, so it's good to know the C7 axle removal is somewhat drama-free.
I will definitely check the breather. Is this accessible if the rear is raised 10" on ramps? Or does breather access and removal require a bit of disassembly ? What's the best way to remove it (on ramps)?
I was doing some research and stumbled across a few posts about early cars having similar leaks especially in colder climates, and that the new seal design that came out in 2015 was supposed to remedy it. Being that my car was built in late 2014, I most likely have the old seal design, although it's strange that the leak started after 10 years as all other examples I was reading regarding seals leaking in cold climates were in 2015.
Another topic that was discussed was a faulty output shaft bearing causing the issue, so it appears the leak is due to either a blocked breather, faulty bearing, or the early seal design. The high mileage may also be the culprit (80k miles, although they have been gentle highway miles primarily, no track days)
I will order the seals and while it's out, I will try to locate the breather and see if I can inspect it closely in case it's clogged.
I will respond back in a couple of weeks when parts get here, meanwhile I welcome any other thoughts/comments/suggestions.
You are going to pull the diff to do the axle seals? Admittedly I have never worked on my C7 diff but I have worked on other brand IRS axle seals. So why not try it w/o pulling the diff. I am thinking that to pull the diff you have to remove the axles. So, once they are out, it might be worth looking into doing the seals w/ diff in the car.
You are going to pull the diff to do the axle seals? Admittedly I have never worked on my C7 diff but I have worked on other brand IRS axle seals. So why not try it w/o pulling the diff. I am thinking that to pull the diff you have to remove the axles. So, once they are out, it might be worth looking into doing the seals w/ diff in the car.
no, I am going to remove the axles only as shown in 96GS#007's photos above. Some cars require the differential to be removed as axles are locked via circlips inside the differential and I was just commenting that I am glad to see C7 axle removal is straight forward.
By the way, where do I find the torque spec for the axle nut when I put everything back?
Rear differential seals
