Differential fluid change - do I need friction modifier?

[J DAMAGE]

My supplement also mentioned the FM, but does not say to add it, its confusing, If you read it a couple times , you start to relize its talking about LS rears, and ours are not, so it confuses the hell out of you, it did me, but I went with mobil-1 75w-140, and it has the additive in it, I can't remember, but I think ruger, NO sorry MCR is the one who said to me , good luck finding diff oil with no LS additives in it.

 

[R1jamn]

My supplement also mentioned the FM, but does not say to add it, its confusing, If you read it a couple times , you start to relize its talking about LS rears, and ours are not, so it confuses the hell out of you, it did me, but I went with mobil-1 75w-140, and it has the additive in it, I can't remember, but I think ruger is the one who said to me , good luck finding diff oil with no LS additives in it.

It is confusing J.
My 2014 SVT Raptor supplement shows
75w-85 premium Synthetic Hypoid Gear Lubricant.
Note #5 (Do not add Additive Friction Modifier to the rear axle.)

I just need to verify what Ford Motor Company put into the rear diff of my '14.
Because they do specify 75w-85 in the supplement.

 

[Gotbitn]

Found this when I was looking for what to use.
https://www.fcsdchemicalsandlubricants.com/main/quickref/axlelube.pdf

---------- Post added at 10:49 PM ---------- Previous post was at 10:45 PM ----------

The main page has lots of info on Ford chemicals.
https://www.fcsdchemicalsandlubricants.com/main/

 

[R1jamn]

Found this when I was looking for what to use.
https://www.fcsdchemicalsandlubricants.com/main/quickref/axlelube.pdf

---------- Post added at 10:49 PM ---------- Previous post was at 10:45 PM ----------

The main page has lots of info on Ford chemicals.
https://www.fcsdchemicalsandlubricants.com/main/

Good Find!!
Thanks for the links.

 

[Vash]

Thanks for confirming. I was pretty sure about the rear end size and bolt config since I just installed a Mag-Hytec F12-9.75 cover. Too bad there's no aftermarket options for the front diff cover. I'd rather not have to deal with gasket maker and dropping the cover to change fluids every 50,000 miles. The front diff is a royal PITA.

 

[R1jamn]

^^

Hey no problem. I'm just trying to get to the bottom of this.
The only piece of the puzzle that remains for me is....What kind of gear oil is in the ass end of my '14 (SVT Raptor Supplement shows 75w-85)

I'm heading down to Van Nuys tomorrow to pick up a Mag-Hytec cover.
It'll sit on the bench for awhile though.
Blackstone labs will get a UOA kit to me in about 1 week.
Then I'll send in the sample. I'm looking at 2-3 weeks for a report.

Just need to verify what Ford Motor Company filled the rear end with before I purchase gear oil.

 

[Vash]

Obviously just conjecture, but based on the reading I've done on viscosity in relation to differentials, 75w-85 sounds too thin for the rear. You have parts that engage and disengage while moving. Higher viscosity oil (75w-140) provides better film strength on parts which provides more protection for high pressure/friction environments. From what I understand, except for Raptors (2012+ I think) that have the Torsen front diff, the front diff is an open diff so I wouldn't expect it to require as high a viscosity hence the 75w-90/80w-90 recommendation.

 

[R1jamn]

^^

I concur.

I ordered a 6x12 tandem axle trailer.
I'll be using it quite a bit this summer behind the Raptor.
So I need to make sure I get the oil specs correct.
I don't need Ford Motor Co. denying warranty for something like diff oil if something should happen.

I fully expect the UOA report from Blackstone Labs to show my '14 has gear oil that is comparable to 75w-140

I just need the peace of mind. (That's how I am)

 

[Vash]

Trust me. I totally understand. I did think of getting an UOA done on my front and rear diff oil, but decided against is since I'd already burned over $100 on synthetic fluids without blowing more on a UOA. I understand what you mean about getting it right though.

I also knew I wanted to stick with Amsoil's Severe Gear series since that's the best they make and that helped narrow down the viscosities for me. I'm looking forward to seeing your UOA results.

 

[R1jamn]

Quick Update

I received a reply from Blackstone Labs.

Here was my question to them:

I need an analysis of the rear differential oil in my 2014 Ford F150 truck.
It's to determine the oil viscosity that came from Ford Motor company and
if it has any type of a "Friction Modifier" in it.
Can you help determine this for me?
I put "industrial" for the type of kit that I need.
But I'm not sure if it would be the correct kit.
Thanks.

Reply from Blackstone Labs:

Thanks for the e-mail. Yes, we can help you with this.
Friction modifier shows up as phosphorus in our testing and the viscosity is
included in our standard analysis.
A kit is on it's way to you.

My kit is on it's way.
Getting a report on the UOA may be quicker than I anticipated.
I'll continue to update everyone as this moves along.