I have been reading up on rear differential servicing and would like to change the fluid now that our truck has gone over 50K miles with most of that towing a 15K fifth-wheel. The look of my rear axle does not match the pictures I see posted in the rear differential servicing threads because we have a set-up that is not sold in big quantity. My rear differential has 10 bolts (not 12 like most) and has what looks like an aluminum cover with fins. The fill plug is right on the rear cover. I am fairly certain the cover is stock because the guy I bought the truck from in late 06 said the only change he made from OEM was to install an AFE ProGuard 7. My trucks specs:

2006 F350
DRW
2WD
Tow Boss Package w/4.30 Limited Slip Axle

I am trying to use my owners' manual to figure out how much gear oil to buy but I don't know which axle I have (the manual shows three axle options). Anybody else have my same set-up?

Is Mobil 1 Synthetic 75W-140 LS the preferred rear differential fluid for my axle or are there other fluid options that I should consider?

 

Here' a recent thread with some general info on the Tow Boss option. Has a link or two might lead you to your answer.
https://www.ford-trucks.com/forums/1...l#post10990976

Of course you can buy what ever brand you like but I would stick to the recommended weight. Also it's listed as limited slip so I believe there's an additive for the clutch pack.

 

I am thinking you have a dana 70

 

I just googled it and you have a dana 110s

 

That's what I used, it already contains the friction modifier so no need to add any, it is very expensive, but I had no chatter while turning. Be advised they do sell a sealant made for this type of fluid as it seems to eat the sealant and I ended up having to redo the gasket cause it started leaking
http://www.permatex.com/products/Aut...tv_sealant.htm
"

 

I am having a hard time confirming this with my own google search. What did you put in the search box or do you have a link? It's not that I question your info. I just want to see why I can't pin down this info myself.

 

homeschoolin, your DRW 2006 F-350 is equipped with a Dana 80 rear axle, and I am 100% positive on that. Wulfman, Dana S110 and S130 rear axles are for F-450/F-550 applications. The Ford Workshop Manual specifies 75W90 weight gear oil, for this rear axle.

 

Also dug up a thread I started on that particular brand https://www.ford-trucks.com/forums/8...ferential.html

 

Thanks for the confirm. That saves me a few $ since the Dana 110s takes 6.6 liters of gear oil vs. 4.0 liters in the Dana 80. Looks like my local O'Reilly's has Mobil 1 75W-90 LS for $10.99/quart. I will get some of the Permatex Gear Oil RTV Sealant and I should be in business for completing the fluid change.

 

its a dana 80

 

How do you find out what Dear Ratio you have?

 

If it's not been changed, check the drivers door sticker for the option code for the gears. List is on ford.com iirc.

 

will list it under "axle" look at chart below to find out.

or refer to this thread https://www.ford-trucks.com/forums/50...m-moved-2.html


The newer 2005-2006 use these codes:



37- 3.73

3L- 3.73 LS

41- 4.10

4N- 4.10 LS

43- 4.30

4L- 4.30 LS

48- 4.88

8L- 4.88 LS

53- 5.38

5L- 5.38 LS<!-- KEN: 1-13-2007: show 300x250 ad-block to non-Club FTE users in the 1st post of every page --><!-- / Ken, end of hack --><!-- / message --><!-- no sigs except when logged in --><!-- sig -->
__________________

 

Did my rear diff fluid change yesterday on my Dana 80. Only a couple of things to note.

First, one of the rear differential tutorials posted here (with pics) showed the good idea of using threaded studs placed in a couple of the bolt holes to make sure the cover is easy to align when replacing. I did not have any threaded studs of the right size, so I used a couple of those stubby golf pencils. I put the unsharpened end in the bolt hole. The pencils supported the cover fine while I screwed in a few bolts. Then I just slid the pencils right out.

Second, my owners' manual said the rear end was supposed to take 4.0 liters of gear oil, which is about 4.2 quarts. I bought 5 quarts and the rear end took all five (about 4.75 liters) when filled to bottom of the fill hole. Not sure what to make of that.

My rear end has the cover with fins on it, if that means anything to anybody or makes any difference. Also, one of the tutorials advised scooping out the old oil laying in the bottom of the housing by hand since some metal particles might gather there. Maybe the fluid capacity guideline of 4.0 liters does not count on that fluid being scooped out.