Transfer Case Fluid Question

Vash · Jul 4, 2011

First, this refers to the t-case on my 2011 Raptor.

So, the stealership recently replaced the rear seal on my transfer case since there was a slight leak at the front of the driveshaft.

I just got around to double-checking the fluid level. It's a bit low. Figured I could just do a quick search and go out and buy some fluid to top it off, but I'm confused now.

As far as checking the level, the service manual states the fluid should be 7mm or about 1/4" below the fill opening on the t-case. I took out the fill plug and there's a kind of metal shelf with ridges that extends below the fill plug. I just saw residue on that shelf and I figure that based on the spec the fluid should be covering that shelf and hitting just below the fill hole. I looked in with a flashlight and saw that the fluid was even with the edge of the shelf as it dropped off into the rest of the transfer case. That's what leads me to belief I need to top off the fluid. I usually have always gone with the practice of filling until the fluid just starts to come out of the fill hole which would make it just about even with the bottom of the hole. BTW, I did the fluid level check with the truck sitting level on my garage floor.

The manual calls for Motorcraft XL-12 Transfer Case Fluid that meets spec ESP-M2C166-H.

I can't find anything non-Motorcraft that references this spec except for some equally hard to find options by Castrol and some other brands.

From reading on various Ford forums it seems the general consensus is that the XL-12 is simply Mercon V ATF.

Is that the case or do I need to just wait to get ahold of my stealership and pick up some Motorcraft XL-12?

If I can use a standard Mercon V ATF, I'll probably go with Mobil 1 Synthetic ATF for the top off.

Can I get some input from any of our Ford Techs on this issue to help me cut through the BS? Thanks in advance and Happy 4th of July!

BTW, I find it odd that Ford specifies Mercon LV for the 6R80 transmission and a special transfer case fluid for the transfer case. The Ford transfer case fluid page doesn't even reference any standard other than the Ford spec: http://fcsdchemicalsandlubricants.c...ansfer Case Fluid&category=Transmission Fluid

jdowens1 · Jul 4, 2011

I would stick with the XL-12 from the dealer. If you add mervon V you prob won't notice a difference. but its a lot easier to keep the same fluid then cross contaminate. Ford transfer case fluid has some difference additives then standard mercon V or ATF. Since the trans case isn't as complicated as the 6r80 in the raptor if you add a different fluid it more then likely won't cause any damage but I would keep with the motorcraft product if at all possible. Just my 2 cents

Vash · Jul 4, 2011

Thanks for the speedy reply. I'll stick with Motorcraft XL-12 Transfer Case Fluid. Just gotta wait until the dealership opens up again tomorrow. Hopefully they have it in stock.

Vash · Jul 5, 2011

Stopped by the dealership this afternoon and they gave me a free quart of XL-12 t-case fluid after I explained my issue. Went by Advance Auto to grab a fill tube and some thread sealant w/ PTFE. Just finished topping off the fluid and sealing everything back up. One less thing the worry about now.

TargetBow · Jan 28, 2014

Vash said:
First, this refers to the t-case on my 2011 Raptor.

So, the stealership recently replaced the rear seal on my transfer case since there was a slight leak at the front of the driveshaft.

I just got around to double-checking the fluid level. It's a bit low. Figured I could just do a quick search and go out and buy some fluid to top it off, but I'm confused now.

As far as checking the level, the service manual states the fluid should be 7mm or about 1/4" below the fill opening on the t-case. I took out the fill plug and there's a kind of metal shelf with ridges that extends below the fill plug. I just saw residue on that shelf and I figure that based on the spec the fluid should be covering that shelf and hitting just below the fill hole. I looked in with a flashlight and saw that the fluid was even with the edge of the shelf as it dropped off into the rest of the transfer case. That's what leads me to belief I need to top off the fluid. I usually have always gone with the practice of filling until the fluid just starts to come out of the fill hole which would make it just about even with the bottom of the hole. BTW, I did the fluid level check with the truck sitting level on my garage floor.

The manual calls for Motorcraft XL-12 Transfer Case Fluid that meets spec ESP-M2C166-H.

I can't find anything non-Motorcraft that references this spec except for some equally hard to find options by Castrol and some other brands.

From reading on various Ford forums it seems the general consensus is that the XL-12 is simply Mercon V ATF.

Is that the case or do I need to just wait to get ahold of my stealership and pick up some Motorcraft XL-12?

If I can use a standard Mercon V ATF, I'll probably go with Mobil 1 Synthetic ATF for the top off.

Can I get some input from any of our Ford Techs on this issue to help me cut through the BS? Thanks in advance and Happy 4th of July!

BTW, I find it odd that Ford specifies Mercon LV for the 6R80 transmission and a special transfer case fluid for the transfer case. The Ford transfer case fluid page doesn't even reference any standard other than the Ford spec: http://fcsdchemicalsandlubricants.c...ansfer Case Fluid&category=Transmission Fluid

When I was planning on changing my fluids I spoke to Chris from Freedom Motorsports and asked what Amsoil fluid he would recommend for the transfer case in my Raptor and he said that he recommends the Amsoil Signature Series Fuel-Efficient Synthetic Automatic Transmission Fluid which is recommended for the Raptor Automatic Transmission. He said that even though Amsoil, on their website, doesn't state that this fluid is correct for use in the transfer case, he said he did a lot of research of the Amsoil products and found this fluid to be compatible for use in the transfer case.
Amsoil's website recommends the following for the transfer case Amsoil Signature Series Multi-Vehicle Synthetic Automatic Transmission Fluid but I went with Chris's recommendation and hope he steered me in the correct direction since he is a dealer of the Amsoil products.

Ruger · Jun 17, 2014

I had the same question. My research tells me that jdowens1 must be correct in that there are additives in the Motorcraft Transfer Case Fluid that are different than Mercon V. The Ford Mercon V bottles evidently say not to use it in transfer cases, and the Transfer Case Fluid bottles say not to use it in transmissions. I'm going to ping Chris at FreedomMotorsports and see if he'd like to weigh in here.

Chris@FreedomMotorsports · Jun 17, 2014

I have done some research on this one as it is very unclear in the manuals, etc. After talking to the Ford tech at my local dealership, it is even more unclear...lol But here is what I have come up with. First, for the use of Mercon V or LV. The LV is an upgraded version of V with a little less overall viscosity, nothing more. But the viscosity of the LV matches up with the Ford transfer case fluid. From what I understand, there are actually two different transfer case possibilities in the Raptor. The first actually has a Ford logo stamped into the back half of the case and that is the one that requires the Ford transfer case fluid from the factory. The other, without the stamp, requires transmision fluid and calls for Mercon V equivalent.

Now, that being said. I was told by that technician that for the transfer case itself, those fluids are so close in formulation that using one in place of the other doesn't hurt anything. There is only a slight difference in viscosity between them and there is only less additives in the transfer case fluid than the transmission fluid overall. So, in essence, you can actually use any of them in the Raptor transfer case without causing problems

That being said, my recommendation for the use of AMSOIL Fuel Efficient transmission fluid is because it is the fluid that meets the Mercon LV application for the 6R80 transmission and when someone is ordering the fluid for a full machine flush, I can send a case of two 2.5 gallon jugs. This provides enough transmission fluid for the full flush and then leaves enough left over to perform the transfer case swap.

Ruger · Jun 17, 2014

Thank you Chris!
Can you be a little more specific about the viscosities and additives, please?
Mine has the Ford logo and was evidently made for Ford by Borg-Warner.

Chris@FreedomMotorsports · Jun 17, 2014

While I don't know the specific viscosity of the Ford transfer case fluid. I was told that the fluid is very similar to the Mercon V in viscosity, with a few less additives like friction modifier. Also, that even though the viscosity overall for Mercon V is around the 190-200 mark and for Mercon LV is around the 155-165, the Mercon LV can be substituted in the transfer case because of the lack of overall load on the internal parts of the transfer case as compared to the load and pressure of the fluid in the transmission. But, that even though the Mercon LV fluid can be substituted for Mercon V in the transfer case, it can't be substituted in transmissions themselves that require Mercon V because the transmissions themselves may not hold proper line pressures with the lower viscosity fluid. Since line pressure, etc isn't an issue in the transfer case, the Mercon LV is fine in them.

Let me also say that I am going off of what I was told by one Ford technician. One that quoted all kinds of numbers and information from memory and was very informative. If someone else can provide information to the contrary, I would love to learn more.

Ruger · Jun 17, 2014

Chris, what are the viscosities of Amsoil...
- Signature Series Multi-Vehicle Synthetic Automatic Transmission Fluid
- OE Multi-Vehicle Synthetic Automatic Transmission Fluid
- Fuel Efficient Transmission Fluid
?

Transfer Case Fluid Question

Vash

FRF Addict

jdowens1

Ford Senior Master Technician

Vash

FRF Addict

Vash

FRF Addict

TargetBow

Full Access Member

Ruger

FRF Addict

Chris@FreedomMotorsports

FRF Gofur

Ruger

FRF Addict

Chris@FreedomMotorsports

FRF Gofur

Ruger

FRF Addict

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