Rear end fluid?

[Hottrodder427]

Does the 2015 it's come with oil in it? When I tried to put oil in it I only got half a quart to go in

[wareaglescott]

Did you buy it from FFR?
I got mine recently from them. I called and asked the fluid status of it. They replied with something to the effect of "I think it comes half full". With that answer there was no question I was draining whatever was in there and starting over. Better safe than sorry for me.

[Hottrodder427]

Good answer, thanks a bunch

[Hottrodder427]

When you drained it, what was in it?

[wareaglescott]

When you drained it, what was in it?

I have not done it yet. Plan to get the fluids tomorrow and do it in the next couple days.

[Lancaster Lad]

To Chime in I received a new 2015 diff from FFR and when I tipped it on it's side oil came out of the half shaft hole.

The oil was light weight like machine oil or light oil to keep things from rusting. No way thick enough for gear oil.

[JRL16]

Drained mine and it was the same gear oil I re-installed with the friction modifier. But there is no way to know how much is in it. When you fill it, the proper amount will not bring it up to the fill hole. It would take at least another pint to bring it up to that point. Don't know if it makes that much of a difference but I put the recommended amount in. The oil is very lightweight and a little expensive too.

[wareaglescott]

I changed mine today. It was clean as it should be and as best I can tell it was full. The instructions call for 3.15-3.3 pints (about 50-53 oz) of the oil and 3-3.5oz of the friction modifier. When I was pouring the old stuff into bottles to take to recycling it was darn close to that amount. Take into account the extra drips in the pan and a few drips on the paper and I am confident I did not need to service it in the first place. My problem was when I called they were not convincing that it came full so there was no way I was going to chance it. Better safe than sorry and at least now I know for sure it is good to go.

[edwardb]

To Chime in I received a new 2015 diff from FFR and when I tipped it on it's side oil came out of the half shaft hole.

Normal. The axles provide the seals to keep the gear lube in the case.


The oil was light weight like machine oil or light oil to keep things from rusting. No way thick enough for gear oil.

I wouldn't be too sure. It's relatively light weight 75W-85 synthetic gear lube. This is what Ford recommends: https://www.fcsdchemicalsandlubricants.com/main/product.asp?product=SAE+75W-85+Premium+Synthetic+Hypoid+Gear+Lubricant&category=Transaxle%20Fluid

Did you get a brand new one or one of the zero mile takeouts? Every zero mile takeout I've heard about, including the one I received, had gear oil in it already. But like others here, I drained it not knowing what I had and refilled it with the recommended lube and friction modifier. Not sure how the actual brand new ones ship. I do know, at least from the pictures, they appear to have plastic plugs in the CV axle holes. I'd be surprised I guess if Ford put anything in there other than the recommended gear lube.

[Lancaster Lad]

Sorry about the bad info on gear lube. This is what happens when an old fart meets new technology.

The last time I worked on trans or rear ends was in the mid 60's. I remember the lube being dark and thick.
After 3 transmissions and 2 rear end rebuilds on my 65 goat I remember. Muscle car and a teenager do not end well.

Cecil
8851

P.S.
The 2015 diff was new from FFR. Came in the genuine Ford Racing box. That was why I thought it was only shipping lube.
The diff came with the plastic shaft covers and it just poured out past the covers. Looks like I may have wasted the lube,
but what is a little more money on this project.

[BEAR-AvHistory]

You are better off dumping it because you do not know if it has the friction modifier added at the factory. Even with the FORD oil listed above you still need Friction Modifier, Part Number XL-3 or equivalent for a fresh fill. Put the XL-3 in then fill with the gear oil till it reaches the fill plug.

On my solid axle I wanted to add a new cover anyway & also gave me an opportunity to check the gear mesh before it was all mounted in the car.

[rich grsc]

You are better off dumping it because you do not know if it has the friction modifier added at the factory. Even with the FORD oil listed above you still need Friction Modifier, Part Number XL-3 or equivalent for a fresh fill. Put the XL-3 in then fill with the gear oil till it reaches the fill plug.

On my solid axle I wanted to add a new cover anyway & also gave me an opportunity to check the gear mesh before it was all mounted in the car.

No way would Ford ship out a new rearend with the wrong oil in it, the liability in doing so would be ridiculous.

[BEAR-AvHistory]

Not saying its the wrong oil. Would think at the assembly plant they would only have 75W-85 synthetic in bulk for rear ends. That said based on the OP getting a pint into a 3.3 pint fill & the "I think it comes half full" comment from FORD tech I would spend a few bucks to be sure it had the .25pint of friction modifier supplement that it needs for the LSD.