75w-140

[rslifkin]

Chances are, the F250/F350 differentials are more over-sized relative to the load they're expected to see (and correspondingly, less stressed). The F150 differential may be more highly stressed, needing the heavier oil to keep wear down.

It's also possible that it's a quirk of the e-locker that led to them spec-ing the heavier fluid.

Chances are, under light use (no towing, etc.), it would live fine on 75W-90, but for the minimal cost difference, I wouldn't really want to find out.

 

[willyreid]

Why not Delo Gear ESI 75w-140
Not much talk here about the Delo gear oil
of which there is the 75w-140 and 80w-90.
Is it too European in formulation?
I'm serious here..

 

[Ramblejam]

Originally Posted By: Fasttimez
that doesn't need it based on usage of the vehicle.


Please provide objective data (not conjecture) that supports this statement.

 

[Fasttimez]

Originally Posted By: Ramblejam
Originally Posted By: Fasttimez
that doesn't need it based on usage of the vehicle.


Please provide objective data (not conjecture) that supports this statement.


My truck doesn't fall anywhere near the term "severe duty" for anything. I don't tow, I don't carry more than a couple hundred pounds in the bed at a time, I don't race my truck or drive it like an idiot, I live exactly halfway between Florida & Maine (Virginia) on the east coast, so not too hot or cold. If just about every other manufacturer specs 75w140 for severe duty use, what does that say about Ford ? Are their gears & bearings so [censored] they need 75w140 from the start ? I'll have to look it up again, but I'm sure I read a paper once where 75w-110 was the lube actually spec'd from Ford, but instead of dropping to a 75w-90, they went up to a 75w-140 to save people from themselves in a sense.

 

[Ramblejam]

You're certainly making many assumptions.

I'll provide some direction here - your truck is equipped with the Ford 8.8. There's plenty of information out there (that's only a few clicks away on Google...) discussing viscosity in this axle.

 

[Fasttimez]

Originally Posted By: Ramblejam
You're certainly making many assumptions.

I'll provide some direction here - your truck is equipped with the Ford 8.8. There's plenty of information out there (that's only a few clicks away on Google...) discussing viscosity in this axle.

You're wrong, my truck is equipped with a Ford 9.75" rear, not the 8.8. My front differential is a Ford reverse cut 8.8. A lot of research has led me to believe that the 8.8 rear was the one with all the issues, in the F150, Explorer & Mustang. It seems the heavier Expedition & F150 equipped with the 9.75 rear had almost zero issues. I bought some Valvoline SynPower Full Synthetic 75w-90 to replace my rear differential fluid. I'll definitely post up if I see anything different such as mpg difference or any ill effects that may happen. I'll be the Guinea pig on this one.

 

[Ramblejam]

You have the 2.7L engine, right?

 

[Fasttimez]

Yes, 2.7 EcoBoost

 

[Ramblejam]

Alright, then.

Why do you think a 9.75" is under your truck?

 

[Fasttimez]

Originally Posted By: Ramblejam
Alright, then.

Why do you think a 9.75" is under your truck?

Because when I ordered the truck, I ordered it with the 9.75" rear which is what you get when you also get the options of Tow Package, Payload Package & 3.73 gears. I've been under my truck & it's a 9.75". The 2.7 engine option has nothing at all to do with axle options. If you order a truck with tow package or payload package you automatically get the 9.75" rear, not the 8.8".

 

[Ramblejam]

Originally Posted By: Fasttimez
The 2.7 engine option has nothing at all to do with axle options.


As the 8.8 is standard and only available on the 2.7L, it has everything to do with axle fitment.

"I don't tow"
"I don't carry more than a couple hundred pounds in the bed at a time"

I wouldn't presume, nor understand why someone with that usage profile would then special order a truck with..."Tow Package, Payload Package & 3.73 gears". My mistake.

To each their own, though; you obviously came into this thread having already determined to know more than the OEM, or anyone else, so I'll end my part of it here. Good luck.

 

[Fasttimez]

Ok bud, why don't you go to the Ford website & "build an F150". Select the 2.7 EcoBoost engine, then select payload package, tow package & 3.73 gears with E-Locker. Tell me then Mr. Wizard what the little magic box says that pops up ? It will say that you MUST get a 9.75" axle for options selected. I can take a pic of my rear differential, door jam sticker or window sticker if you like.....
The 8.8" is standard axle on ALL F150's, it's only when you add options like 4x4, tow package, payload package that you move up to the 9.75" rear. You're right, I don't tow or carry anything heavy, but I ordered my truck like that anyway....it's a lot like a gun, it's better to have it & not need it, then need it & not have it.

 

[Fasttimez]

It's very easy to tell a 8.8" rear from a 9.75" rear. The pumpkin looks totally different. The 8.8" is very symmetric in shape, the 9.75" looks like a sideways trapezoid. Guess what, mine looks exactly like sideways trapezoid, not to mention the sticker wrapped on the axle tube that has 9.75 printed on it, or the fact that I ORDERED my truck & verified it had exactly what I ordered before I took delivery.

 

[Inspecktor]

.
Originally Posted By: Fasttimez
Ok I ordered my truck like that anyway....it's a lot like a gun, it's better to have it & not need it, then need it & not have it.
That is my thinking on gear oil...

 

[zeng]

Originally Posted By: Inspecktor
That is my thinking on gear oil...


+1.

When both grades are recommended, would you select a thicker X grade gear oils or a thinner Y grade?

 

[Fasttimez]

Originally Posted By: Inspecktor
.
Originally Posted By: Fasttimez
Ok I ordered my truck like that anyway....it's a lot like a gun, it's better to have it & not need it, then need it & not have it.
That is my thinking on gear oil...

I can't argue with that....lol

 

[KD0AXS]

Originally Posted By: Fasttimez
why don't they use it in their F250-350 trucks


They do. Not only does my F-350's owners manual call for 75W-140, there's a tag right on one of the diff cover bolts that says "75W-140 SYNTHETIC ONLY".

The front axle however, does just call for regular 80W-90.

 

[Fasttimez]

Originally Posted By: zeng
Originally Posted By: Inspecktor
That is my thinking on gear oil...


+1.

When both grades are recommended, would you select a thicker X grade gear oils or a thinner Y grade?

It's really a tough decision in my own mind I guess. I'm having a hard time thinking Ford actually needs 75w-140 fluid for every axle application, when MOST other manufacturers spec either 80w-90 or 75w-90, & only for severe duty spec 75w-140. Do they all know something Ford doesn't, or is it easier for Ford to just say use 75w-140 in everything, knowing it'll suffice for severe duty applications & be overkill for grandma going to get groceries....lol. I know I'm being difficult here, I do apologize for being stubborn about this subject. I've decided to try the Valvoline SynPower 75w-90 which carries every certification a 75w-90 oil can have, plus its readily available. Hopefully it all works out, I'll report back after I've logged some miles. Thanks for your responses.

 

[Fasttimez]

Originally Posted By: KD0AXS
Originally Posted By: Fasttimez
why don't they use it in their F250-350 trucks


They do. Not only does my F-350's owners manual call for 75W-140, there's a tag right on one of the diff cover bolts that says "75W-140 SYNTHETIC ONLY".

The front axle however, does just call for regular 80W-90.

Do you have the Dana or Sterling axle ? Don't know if it matters though. My dads F550 with Dana 135 calls for 80W-90, I can't imagine your F350 sees more load than his F550 but it gets along fine on that "junk" 80w-90....lol

 

[Fasttimez]

The only reason I keep dragging this on guys is because Ford changed over to 75w-140 spec around 2002-03. Their spec was 75w-90 or 80w-90, can't remember. They actually had their techs replace the fluid & tag on the rear if they came in filled with anything other than 75w-140 later on. What's weird also is the Dana 60 or 80 axle used in a different manufacturers vehicle doesn't spec for 75w-140, it specs for 80w-90....how's that even possible....same axle, different oil specification because it's a different OEM. Just some thoughts.