Synthetic differential fluid - 2 questions?

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DR1

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My vehicle - 2000 Ford F150 4x2 4.6V8

1) Is this what I should use? Synthetic Gear Lubricant, SAE Grade 75W-90

2) Is O'Reily brand "synthetic just as good as Mobil 1 ?
 
I am unaware of any conventional gear lube that is 75w90... only synthetics in that grade. My only concern would be whether your diff has limited slip therefore you would need to purchase a seperate LS additive or buy the gear lube with it already in there in which the bottle will say so.
 
According to what I see in the 2000 Ford F-150 Owner's Manual, your rear axle should use 75W-140 which is definitely a synthetic gear oil. IMHO Amsoil is the best, but M1, SuperTech, Castrol or the like would be just fine (need to check on the LS additive as CharBaby suggested though).
 
Originally Posted By: 2015_PSD
According to what I see in the 2000 Ford F-150 Owner's Manual, your rear axle should use 75W-140 which is definitely a synthetic gear oil. IMHO Amsoil is the best, but M1, SuperTech, Castrol or the like would be just fine (need to check on the LS additive as CharBaby suggested though).


Cant stand it when folks say "this is the best" There is no "Best" haha. Amsoil is as good as many other products out there and people on these forums know this. So lets keep brand Bias out of it.

OP,

As long as you follow Fords Recommendations of what gear oil to use, you are fine. Just check your manual to verify, and buy a brand you have heard of. If you are not sure who makes O'Riley Oil? Then buy something else that you have heard of, or at least know who made it.

Good Luck
thumbsup2.gif



Truck On!!


Jeff
 
Originally Posted By: Jeffs2006EvoIX
Originally Posted By: 2015_PSD
According to what I see in the 2000 Ford F-150 Owner's Manual, your rear axle should use 75W-140 which is definitely a synthetic gear oil. IMHO Amsoil is the best, but M1, SuperTech, Castrol or the like would be just fine (need to check on the LS additive as CharBaby suggested though).
Cant stand it when folks say "this is the best" There is no "Best" haha. Amsoil is as good as many other products out there and people on these forums know this. So lets keep brand Bias out of it.
If you can read, you will see that I clearly said IMHO, which means In My Humble Opinion and I clearly noted other brands as well. No one is forcing you to accept my opinion, so climb down off that ivory tower.
 
If I gave my VIN# to my local ford parts dept could they tell me if my truck is Limited slip?
 
Originally Posted By: lawnguy
If I gave my VIN# to my local ford parts dept could they tell me if my truck is Limited slip?
I would think so. BDCardinal on here can probably tell you as well (he is a Ford parts advisor and an all around great guy).
 
I just called my local ford dealer parts dept. I gave them the last 8 of my vin. He told my my truck had a limited slip,and the rec diff fluid is 75w 140
 
Originally Posted By: lawnguy
I just called my local ford dealer parts dept. I gave them the last 8 of my vin. He told my my truck had a limited slip,and the rec diff fluid is 75w 140
Just need to find gear oil that already has the LS additive in it or purchase a bottle of it and add it to the axle after filling it. Ford sells it (For a complete drain and refill, some limited-slip axles require addition of Friction Modifier, Part Number XL-3 meeting Ford specification EST-M2C118-A).
 
Originally Posted By: 2015_PSD
Originally Posted By: Jeffs2006EvoIX
Originally Posted By: 2015_PSD
According to what I see in the 2000 Ford F-150 Owner's Manual, your rear axle should use 75W-140 which is definitely a synthetic gear oil. IMHO Amsoil is the best, but M1, SuperTech, Castrol or the like would be just fine (need to check on the LS additive as CharBaby suggested though).
Cant stand it when folks say "this is the best" There is no "Best" haha. Amsoil is as good as many other products out there and people on these forums know this. So lets keep brand Bias out of it.
If you can read, you will see that I clearly said IMHO, which means In My Humble Opinion and I clearly noted other brands as well. No one is forcing you to accept my opinion, so climb down off that ivory tower.


Yes I did read that. But you still said "the Best" regardless. At any point anyone says something is "Best" is an opinion so you basically just repeated yourself.

There is no Ivory Tower, unless you placed me on one.

Maybe just say you like Amsoil, give it a try, rather than "IMHO ITS THE BEST" mmmmmm But thats just me.


Jeff
 
I just put Valvoline Synthetic( it says for limited slip on the bottle) 75W90 in my 2017 Jeep w/trac lock differential on a 1000 mile round trip. Rear diff is quiet as a church mouse.
 
From a "risk" standpoint, the LSD additive is the more important thing here. Not enough, or the wrong kind, and the clutches will wear prematurely.

I'm not sure of OEM/dealer fluids, but I find with every aftermarket diff goop in an LSD, the "includes Limitied slip Modifier" is never right. Usually not enough, even with amsoil. I use amsoil and find that their fluid, plus about 1/3 of a tube of their LSD modifier, is about right in my tundra.

We tow a TT on the interstate, and the diff gets plenty hot on hill climbs. I'm a fan for synth in the driveline.

-m
 
If you're going to work it, Royal Purple Severe Gear full syn gear oil is pretty hard to beat. Now if you're just putting around empty, just about any decent 75W140 with LSD additive would be more than enough.
 
Typically, store brand gear lube is good for topping off vehicles equipped with LSD. (ie a temporary fix meaning you're better to top off than burn up your diff.) That is it.. it's not replacement worthy. Someone please correct me if I am wrong.

M1 and Synpower will have your LSD additive. Synpower being somewhat cheaper. Both are exceptional products.
 
In Gear Lubes, there are 3 bests that only people as smart as me and 2015_PSD (I'd estimate 37.5% US population) know about. Amsoil, RL and Schaeffers. Anybody with a lick of sense knows that. I 'm not sure what a "lick of sense" means but I do know the 3 BESTEST gear lubes and I listed them in alpha male order. That is a fact Jack.
smirk.gif


Is Goodyear just as good as Michelin?
Is Great Value Toilet Paper just as good as Costco?
Is Pennzoil Ultra just as good as Amsoil SS?
Is Samsung just as good as Apple?
Is ATT just as good as Verizon?
Is a [censored] degree just as good as a Welding Degree?
Is putting the dishes up wet as good as drying them first?
Therefore, if you follow my logic without understanding, I have proven the 3 best Gear Oils. Amsoil, RL, and Schaeffer.

I need to go check my glucose.
 
Originally Posted By: lawnguy
I just called my local ford dealer parts dept. I gave them the last 8 of my vin. He told my my truck had a limited slip,and the rec diff fluid is 75w 140


I would use any 75w-140 and add half a bottle of the Ford friction modifier. Drive around in figure 8's in a parking lot and see if you hear any popping or chirping from the rear axle. If you do, add the rest of the friction modifier and repeat.

I used Amsoil 75w-140 in my F350 with a limited slip, and ended up having to add the full bottle of Ford friction modifier.
 
I typically stick with OEM for gear fluid (GM has a nice grape smelling fluid) but consider Amsoil as well. Expensive but well work it.
 
I thought I was the only gear oil sniffer. It is amazing to me how much different they smell. One of my ATF fluids smells like cat urine.
 
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