Transfer Case Fluid Change: A bit of clarrification

[BootyDo]

Hi All,

I'm looking to change my rear and front differentials this weekend. In addition, I'm tackling the transmission with a new filter and all as well. I don't think anything has ever been done and I just hit 100k. But what's the deal with the transfer case? Laugh if you will, but I never knew that was part of routine maintenance. So after searching the boards, I'm seeing some varying information.

Is there a how-to or list of what I need and capacity on a 2006 V8 4x4, (no AWD and has the 6 speed auto). Some decent videos, but it seems like Mercon is a no-no, but is that just on later 4th Gens?

TIA!

 

[07EddyB]

The transfer case is the easiest of all of them. You have two plugs - a higher fill plug and a lower drain plug. Loosen the fill plug first to make sure you can refill it before you drain it. I was confused by the different Mercon requirements between different years so I just went with a Valvoline transfer case fluid that is supposed to meet all specs. As I recall, I used just shy of two quarts - the capacity listed in the manual is about 1.75 I believe. Filling is easy - you will need a fluid pump of some sort for the transmission - use that for the transfer case as well. Basically you just fill it up until it starts running out of the fill hole.

 

[BootyDo]

Thanks Eddy! That sounds super doable. Adding it to my list now. Do you mind if I ask what tools are needed? I only have 1/2" drive and I think I need a 3/4" expander for the rear differential. And is there any need to put some sort of RV sealant on the plugs?

Thanks again!

 

[Explorer_PL]

As Eddy said, it takes less than 2 qts, get Motorcraft XL12 transfer case fluid. A little of RTV will not hurt, I never used it and no leaks, but probably I should have. The plugs are 3/8 or 1/2 inch drive. Just the rear diff is 3/4.
I used a cheap HF hand pump.

 

[07EddyB]

i believe the plugs are 3/8 square drive so if you only have a 1/2 ratchet then you might have problems without a 1/2 to 3/8 adapter. I just used a 3/8 extension on a ratchet and it fit right in. I didn't add any sealant to the plugs - just left the old stuff on them. FYI - be careful reinstalling because I don't believe the plugs ever seat - you can theoretically screw them in until they fall in. Not sure - I chose not to test that theory.

 

[Mbrooks420]

The plugs aren’t tapered pipe threads? I can’t image them being straight through tapped holes. They should seat against the treads.

 

[07EddyB]

It's been a month or two since I did the transfer case but I remember looking at the plug thinking it was straight and a fine thread. But there may be a taper on it - just not enough for me to notice.

 

[CDW6212R]

The plugs are NPT, they get tighter as it tapers. They don't need sealant, and don't need to be very tight, just good and snug. They won't leak if the threads aren't rusted away.

 

[Littleant]

+1 on the Motorcraft XL12 transfer case fluid. Do not use Mercon V trans fluid

 

[07EddyB]

The plugs are NPT, they get tighter as it tapers. They don't need sealant, and don't need to be very tight, just good and snug. They won't leak if the threads aren't rusted away.

Thanks for the clarification. I don't want to be 'that guy' that starts an unfounded internet 'fact'.
I probably should have tightened mine more but they don't leak so all is well.

 

[CDW6212R]

Thanks for the clarification. I don't want to be 'that guy' that starts an unfounded internet 'fact'.
I probably should have tightened mine more but they don't leak so all is well.

I'm sure your's are fine, the plug threads fit well and aren't likely to back out.

 

[BootyDo]

Hi All,

First - THANK YOU! I went ahead and picked up 2 quarts of XL12 transfer case fluid and one of those pumps. Does anyone know the capacity on this thing? I thought it was under 2 quarts but one YouTube said "2 quarts". Not sure if that was a F-150 in the video or not.

Duh! I just reread your first post Eddy - 1.75! Idiot me. Thanks!

 

[Tike]

ive userd Mobile one ATF and havent had a problem. checked the fluid after 15k was good. 30k was fine i do it every 45k. just my 2 cents.

 

[Drewmcg]

+1 on the Motorcraft XL12 transfer case fluid. Do not use Mercon V trans fluid

Update on an older thread (in case someone searching finds it, like I did): I just spoke with my local Ford dealer parts guy, who I trust (Varsity Ford Ann Arbor, MI), who says "Mercon LV" is now what Ford specifies for the 4th gen Explorer 4 X 4 transfer case. He was very clear (twice) that the Mercon "Transfer Case Fluid" (aka "XL-12") has been "obsoleted" by Ford, and replaced with Mercon LV as the recommended part. NB: this is (as Tike noted) *not* Mercon V.

As a bonus, the dealer sells LV for $6 a quart, which is roughly 1/3 the price of what I can find the obsoleted Motorcraft Transfer Case Fluid online at Amazon.

 

[Littleant]

Motorcraft® MERCON® LV Automatic Transmission Fluid (ATF) READ LAST LINE AT BOTTOM. DO NOT USE IN TRANSFER CASE (USE XL-12)

• Premium-quality ATF for Ford, Lincoln and Mercury transmissions
• Provides excellent performance in electronically controlled automatic transmissions
• Manufactured with high-viscosity index, premium-quality, hydroprocessed base oils and specially designed performance additives
• Provides excellent shifting characteristics at high and low ambient temperatures, and guards against transmission shudder
• Offers excellent thermal, oxidation and shear stability, as well as good low-temperature fluidity
• Provides wear protection and inhibits the formation of gum, sludge, lacquer and foam
• Helps prevent rust and corrosion
• Dyed red for easy leak detection
• Not for use in applications where MERCON® V, MERCON® SP, Continuously Variable Chain Type Transmission Fluid, Motorcraft® Premium Automatic Transmission Fluid, FNR5 Automatic Transmission Fluid or Type F Automatic Transmission Fluid is recommended
• Not for use in transfer cases

 

[Drewmcg]

With respect, Littleant is wrong, though it's easy to see why he's made this mistake. That is an older webpage that, unfortunately, has not yet been taken down, as noted on this comprehensive blog here: Ford Full Size 4x4 Transfer Case Fluids . As seen on the updated webpage here, MERCON® LV Automatic Transmission Fluid , LV is now the recommended fluid "for use in all transfer cases."

Think about it: why would Ford stop selling XL-12 without a substitute? Makes no sense. No doubt the dwindling supply of XL-12 will work just fine. Feel free to pay three times as much online if it gives you a warm fuzzy to do so, but it's truly pointless.

 

[Littleant]

Thank you Drewmcg for posting the correction. I appreciate that. Just did a fluid change with the xl-12 about 300 miles ago in my 2010 Mountaineer. I will be changing my fluid to the Mercon lv this weekend. Again thank you for posting the correction and the link.

 

[Tike]

as long as you use either and do regular changes you'll be fine its regular maintenance thats the real killer here yall!