I'm assuming this would be the forum to post this question in? I'm planning on changing the rear diff fluid on my new to us class A MH. I'm assuming (again) that there are drain and fill plugs on the rear axle? I can't verify that anywhere and the MH is in storage until I bring it home next weekend for our last trip, so I can't climb under and look at it. IDE like to know so I am prepared to do it.

And yes I know it's filled for life, but I've never subscrbed to that way of thinking. I've seen filled for life trans fluid after 50k miles! And BTW I'm doing the trans and brake fluid also. The MH has 40k miles on it.

 

Do you know what the GVWR is? That'll determine what axle it is, but it's definitely a Dana 80 or bigger.

Problem is, the way to drain a Dana 80 is to remove the diff cover. Dana 80 Differential Fluid Replacement & Axle Specs

With fluid that new, you might want to pump it out the fill hole. I've done it on a Sterling 10.5" that way, and even an 8.8" Ford in my ;'96 T-bird.

The fill plug should have a magnet on it - when you remove that, check for a lot of metal. A small amount that looks like paste is OK. But chunks are bad

The bigger axles, S110 and above, seem to have drain plugs: https://media.spicerparts.com/cfs/fi...mQtJg/LM072012...

 

It's on a 24klb chassis. It's definitely not an 80. There is no diff cover. I did some research and it looks like an S110. If so it has a drain plug at the bottom of the axle housing.

 

It is neither a Dana 80, nor a Dana 110.

If the GVWR to your 2012 F-53 is 24K lbs, then the rear axle to your unit is a Dana S17060S.

This is a serious axle, rated for 17,500 lbs. This is the largest axle that Ford installs in a stripped chassis, which includes the 26K GVWR F-53 chassis.

A similar design and rated axle can be found on some models of the F-650, that is now made of a newer "lighter" structure (although is equally rated as far as GAWR).

The Dana S17060S is old school brute and brawn. This was the axle that Noah used under the Ark, before the rains came.

Prepare to buy axle fluid by the gallon. Multiple gallons, in order to fill it. Use a 500,000 mile (OTR) rated synthetic from Dana's approved axle lubricant list. Might set you back a few hundred dollars for the fluid, but you won't need to change it again.

 

Ok thanks. That makes sense. I knew it was big and very heavy duty. Yes, I'm only changing it this one time because it's new to me. After this then I'll know all the fluids have been done.

 

Being a 2012 it should have 75-90 synthetic oil in the axle now which is a 250,000 plus mile oil, at 40k miles you can change it if you want but your just waisting time and money.
That axle should hold around 4-5 gallons, search shows 5 gallons costing around $125-150, that's $100 per bucket less than I was paying 15 years ago before I sold my last big truck.