Differential fluid change - do I need friction modifier?

[Madcowranch]

This is straight from my 2012 Raptor Supplement. I have highlighted the areas pertaining to this discussion

---------- Post added at 09:12 AM ---------- Previous post was at 09:06 AM ----------

Can't attach a pdf?

2012 raptor supplement: https://dl.dropboxusercontent.com/u/12246588/axle info from 2012 raptor supplement.pdf

2012 raptor owners manual: https://dl.dropboxusercontent.com/u/12246588/axle info from 2012 owners manual.pdf

---------- Post added at 09:15 AM ---------- Previous post was at 09:12 AM ----------

Since the Raptor supplement does say to add the friction modifier without specifying electric locker or LSD, then I assume we still have to add the friction modifier?

That's interesting. The 2010 manual does not have that 2nd entry with the friction modifier part.

---------- Post added at 08:27 AM ---------- Previous post was at 08:23 AM ----------

Geez Madcow, just turn it into a street queen too while your at it.

Thats all he does is drive up and down the hwy. Blames it on alignment machines but we all know the truth. How about that for snake oil.

Sounds about right. He drove like a Sally at raptoberfest, even got stuck

Guys guys, you know that I do not like to get my little princess dirty. I just rub her at night with a soft cloth.

 

[Ruger]

That's REAL interesting! In the 2011 Supplement the requirement for the 4 ounces of friction modifier is in the body of the chart itself and is therefore not a footnote as it is in the 2012 Supplement. But the specification is identical and the fill instructions are identical. I would follow those instructions to the letter for the 2011 and 2012 models without question.

MCR, you might want to cross-reference the differential part numbers for your 2010 model against those of the 2011 and 2012 models. If the part numbers match, then I think that you can assume that the need for a friction modifier became apparent after your Supplement was printed and that you should use the additive. You could inquire after this matter at your local Ford dealer, but the answer you get will depend upon how astute the guy is that you ask and whether he cares enough to look into it. It's always better to do one's own research and analysis.

 

[Humvee21]

This topic has been discussed. Just never received a conclusive response.

http://www.fordraptorforum.com/f7/rear-diff-oil-change-friction-modifier-20398/

http://www.fordraptorforum.com/f7/changed-front-diff-fluid-today-30861/

However, with Pirate Air's knowledge and experience, I am going to assume he's right

 

[Ruger]

However, with Pirate Air's knowledge and experience, I am going to assume he's right

Right in the sense that using a synthetic gear oil with friction modifiers blended will suffice? Probably, but I would read the label and be certain that the manufacturer indicates that the product specifically satisfies the Ford factory requirement for a differential gear oil friction modifier.

 

[Humvee21]

Right in the sense that using a synthetic gear oil with friction modifiers blended will suffice? Probably, but I would read the label and be certain that the manufacturer indicates that the product specifically satisfies the Ford factory requirement for a differential gear oil friction modifier.

Right in the sense that I think he is a good technician and will likely find us a good answer

 

[Red]

My 2013 Manual calls for a friction modifier.

 

[Ruger]

Thanks, Red. That's 3 years - 2011, 2012, and 2013 that require the friction modifier. I think we may have a trend here.

 

[Madcowranch]

The only brand Auto Zone had in 75w-140 was Royal ***** I mean Purple and, guess what, it has the friction modifier in it already. I'm guessing Pirate is right that most of them already have it added.

 

[pirate air]

So, I've looked at synthetic 75w140 in, royal purple, red line, lucas, amsoil, mobile one, valvoline, castol, and my personall choice, schaeffer #167. They all contain an additive package specifically for LSD and all meet or exceed API GL-5. Not to mention all claim to have some flavor of extreme pressure formulated for hypoid gear sets. In other words, the fluids are designed, tested, approved, and backed by companies with long standing reputations.

It's still beyond me the reasoning to put a fluid that was specifically engineered for limited slip clutch style differentials in a non limited slip differential. I checked with eaton (who makes our diff) and still no mention of needing friction modifier. Maybe its a typo, or part number change, or maybe the supplier of motor craft 75w140 changed the recipe after 2010 and it was thought the modifier would make up for something. I dunno, I can't even find any benefit to friction modifier outside of clutch packs. If it was that big of a deal, 2010 owners would be getting recall notices that gave you a piece of paper with up dated info to stick in your owners manual. Nothing's come thru, no recall, no tsb, no news flash, no blown up differential due to lack of friction modifier. I'm not chasing after a problem that doesn't exsit.. I'm going to stick with pure #167, and drive her like hell.

 

[Ruger]

You're a wonder, Pirate. Thank you for running this to ground.

This thread ought to be archived in some way so that nobody has to plow this field again.