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Discussion Starter · #1 ·
I'm getting mixed signals as to what my axle is (which is important since the fluid was recently changed).

I asked the mechanic (this was done just before I purchased the vehicle) if my diff was free float or limited slip. He said float.

My door tag says my axle is F2 which is supposedly a 4.10 limited slip.

I've attached the tag. I have limited experience with Fords, but if I recall correctly the limited slip diffs usually have an "LS" between the 4 and 10. Maybe someone here can confirm this.
 

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The tag shows that it is a 4:10 open diff.

It isn't uncommon for someone to switch out the rear end if they have had a failure. At times it is easier to swap rear ends than it is to fix them.

Also don't worry about it being a open diff. From what I have heard the limited slip is as close to a open diff as you can get.
 

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Discussion Starter · #3 ·
I do a lot of driving in loose sand. What do you think of installing a lunchbox locker like a PowerTrax? Is this diff an 8.8? Still don't know what all the numbers mean other than a 4 and 10
 

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Discussion Starter · #4 ·
...or a Detroit True Track (seems better for pavement)
 

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Any locking rear end is going to be better than a open diff or even the limited slip that in in these trucks.

The rear end is a Sterling 10.25
 

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...free float or limited slip.
Part of your confusion comes from terminology. Floating & limited slip refer to independent characteristics of the axle assembly.

A differential (the mechanism that allows driven wheels to turn at different speeds) can be open, limited slip, torque-biasing, part-time locking, full-locking, or a spool (which isn't actually a differential, but it takes the diff's place). This diagram's caption explains the differences:



A drive axle (the mechanism that transmits driveshaft torque to the tires AND supports the vehicle's weight) can be a full-floating design (no vehicle weight on the torque axleshafts) or a semi-floating (weight only at the outer ends). These show the 2 configurations for a Sterling 10.25":

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...the limited slip diffs usually have an "LS" between the 4 and 10.
 

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Discussion Starter · #7 ·
What part of the code translates to a 10.25? For a minute I thought this was a dana 80
 

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This shows how to read a Dana tag:



This shows a D80:



Their captions link to the Dana site for more-specific information.
 

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The plot is getting thicker.

You need to tell us about your vehicle. You have posted in the truck section so all of us are supposing that you have either a F250 or F350 which has a 10.25 Sterling.

Now we are starting to learn that you have a van. It just might be a Dana 80.

You need to fill in your signature or post what you are driving for the right help.

To fill in your signature you just need to go to "My Account" that is up in the dark header box towards the top of the screen. Then on the left hand side go down to "Settings and Options" and then "Edit Signature"
 

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What model of truck is this? Wait, is this the van/bulance in your sig? From what I can gather, F2 is for a dually F350 4.10. Oh I suppose an ambo would be a dually. At this point, you may just want to remove the cover.

Generally, axle codes beginning with a letter are LS.
 

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The photo isn't very useful - what's cast into that web? Is it "70HD" upside-down? Did you look for any other markings embossed into the casting or on the tubes?
 

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Go to this link and then scroll all the way to the bottom. There you will see the diff covers and what they attach to. Then you will know what rear end you have. The picture is a little hard to see but if you look at it on a computer screen and not a phone you should be able to tell the difference.
 

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Discussion Starter · #17 ·
Go to this link and then scroll all the way to the bottom. There you will see the diff covers and what they attach to. Then you will know what rear end you have. The picture is a little hard to see but if you look at it on a computer screen and not a phone you should be able to tell the difference.
Unfortunately, that really tiny image doesn't differentiate between Dana 50, 60, 70, or 80
 

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Discussion Starter · #18 ·
PS: The rear diff probably isn't original since the door code says I have an LS and I definitely do not (grumble)
 

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^^^^^ That may just be the LS clutches getting tired, and/or the lube needing replaced. One of our '95s has a 3.55 LS (C9), and it's not really noticeably different from the other truck with an open 3.55 (39).
 

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Discussion Starter · #20 ·
Well, this was from a mechanic who changed the lube (previous owner; I would never let a grease monkey change my gear oil).

That said, I haven't looked inside the housing myself.
 
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