Ford AWD PTU fluid always black

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Hi guys.

I have done a few fluid services on the Power Transfer Unit gearboxes found on the Frd Explorer, Edge and other related models that use the same PTU.

Every time, the fluid is black, pitch black. We know that previously, Ford only recommends a fluid service every 160k km (100k mi) only under severe conditions. But the models I work haven't been stressed as such.

Any idea why it is so black and thick under short lifespan and duty conditions?
 
From everything I've read about these its a combination of issues. The main items being that it holds a small amount of fluid to begin with, and that in applications like the edge the cat is next to it causing it even more heat in normal driving.

What kind of mileage are you changing the fluid on them at?
 
About how many miles did the vehicles have on them when serviced? Hopefully, not around 30k or so.
 
These get very hot. I can't find it for the life of me, but I recall reading a thread on an Explorer (?) forum where a guy sent in a for a UOA. His Explorer had a cooler and Blackstone still said to change it every 5k or so.

My dad's SHO has one that isn't cooled. If it had the track package, I believe it would have came with one. Darn thing doesn't have a drain plug and everything is shoe horned in there.

Motorcraft 75w-140 is a tad thicker than the Mobil 1 75w-140 if that matters to anyone. (Spec'd fluid)
 
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I'm typically changing them from 30k - 90k mi mark. Pretty wide range to be honest.

I do take a special moment each time to talk to the customer about why this is important, and while I am able to impress the importance and severity of this issue, I usually don't win:)

All that I see from YouTube reports is heavy sludge buildup inside the case. About 1/4 cases I get in have a thick paste inside the gearbox. I don't recall seeing one with clear or even a light grey -- ever.
 
Originally Posted by bdcardinal
The one in my mom's 2014 Fusion has both drain and fill plugs so I will be doing that at the next oil change when it gets to 35k.


That is pretty cool. I have never seen a drain plug on a PTU (the older Escapes had them) on any PTU that has rolled in here. We also rarely ever see Fusion/Tarurus AWD models.
 
In oddball cases, lube will turn black if there is electricity flowing across a bearing or gearset. Any chance there's electricity going through your PTU? Maybe missing a ground strap somewhere?
 
There shouldn't be any electricity. There were models that have an external cooler and I seem to remember some either having a temp sensor or a level sensor.

My mom wanted the AWD Fusion. She was coming from a Grand Marquis and the thought of FWD scared her. This is actually her first car that was not a RWD V8 Ford/Mercury.
 
Originally Posted by bdcardinal
The one in my mom's 2014 Fusion has both drain and fill plugs so I will be doing that at the next oil change when it gets to 35k.


Happy Birthday
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! Our 2017 Explorer with the 2.3 EB has a drain plug and it's easy to access the fill plug. If you're on a lift it's a 20 minute job. With the 2.3 EB the exhaust is not near the PTU to add heat. I had the factory fluid changed at the dealer at 9,000 miles. I had it changed again at 22,500 miles but with Amsoil Severe Gear 75W-140 by my mechanic. I watched him do it. The dealer installed fluid came out golden and flowed easily. It had 13,500 miles on it. I'll leave the Amsoil in for 25-30,000 miles. I saw those videos of the thick or solid 75W-140 and they scared me to do those early changes. But now I feel much more comfortable to go longer. Also our has a greater capacity than the older ones, it holds 24 oz vs 18 oz.

Whimsey
 
I have an 15' Fusion and it has a fill and drain plug as well. I drained it at 45k and again at 90k and it was gray both times. The Blackstone report said that it was exceptional when compared to the universal averages. It only holds 12oz. However, my rear differential had a lackluster report and Blackstone recommended changing the fluid earlier than the 45k oci that I was doing. So instead or going another 45k on the PTU, I change it at 30k when I change the rear differential fluid.
 
What fluid does it use? The transfer case on the wifes new F350 used LV atf and 75W-85 in the rear diff and 80W-90 in the front/
 
Originally Posted by CT8
What fluid does it use? The transfer case on the wifes new F350 used LV atf and 75W-85 in the rear diff and 80W-90 in the front/


There at one time was a special fluid, but now they call for 75W140.
 
Lack of cooling.
I have in the past posted what I would consider a 'fix' for the issue. Basically replace the drain and fill plugs with hose fittings. Then from the drain we go to an electric lube pump, which they make for this type of deal where you are pumping heavy gear lube. The pump will push it to a standard 3/4-16 filter head with the largest filter that can feasibly fit somewhere on the vehicle. Which could be up to a 2qt filter. From there we go to up front to a oil-to-air cooler then loop back to the fill plug.
I think the fill cap on these is like a pint or so. IF you could fit the 2qt filter somewhere then add in the oil in the lines and the cooler it could end up in the 3-4qt capacity range.

But no one has taken me up on trying it out. :p
 
Fittings? Tried that on Explorer Sport hoping to get a Futomo valve in it … no room.
Gave up and traded for Tahoe … (and a Z71 for me) …
 
Originally Posted by 4WD
Fittings? Tried that on Explorer Sport hoping to get a Futomo valve in it … no room.
Gave up and traded for Tahoe … (and a Z71 for me) …

I have access to an Explorer Sport now so Ill look at it. I am curious. I wont be able to do anything because its not mine, but...
 
I must be the luckiest SOB on the planet. Mine (Taurus SHO) may have been changed @ 50-somethingK when the dealer installed the vent tube as per the TSB (I was leaking from it) and now at 127k I've not thought twice about it. Doesn't make noise and as far as I can tell AWD still works (nail the gas in the rain and she hooks up and goes). Will find out in the first snow if it still works but I guess it will.
 
Originally Posted by CT8
What fluid does it use? The transfer case on the wifes new F350 used LV atf and 75W-85 in the rear diff and 80W-90 in the front/


cardinal is correct, it is SAE 75W-140.

From my experience of doing these, since I have never seen a drain plug and probably only seen a handful of AWD Fusions/Tarurus, is to take a small ratchet and reach up and over the subframe member to access the plug. Basically reaching from the back of the PTU. The vents are particularly difficult to access, but not entirely impossible.

Your wife's vehicle has a conventional 4WD setup. These vehicles we are speaking of have what is called part-time 4WD. Power is sent to the front all the time, the PTU sends power to the back diff which has a clutch to actually send power to the wheels. Usually is automatically controlled, some do have a manual override. Not the same thing as conventional 4WD or true full time AWD with a center differential.

ATF is pretty standard fill in most transfer cases, but some do take gear oil (most Toyotas). Most shops cheap out and use 75w-90 for 75w-85. Toyota specs a 75w-85 GL5 fluid for some of their rear ends (Tundra for instance), it's not quite the same as regular old GL5 stuff.
 
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