Power Transfer Unit (PTU)- 75W-140 recommendations

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Just checked and the latest one we replaced for the CHP had a cooler on it. The cooler comes with the PTU. I will try and take some carnage pics when it calms down a bit here.
 
All the interceptors have a basic cooler, the cooler option I was asking about earlier is supposed to be a heavy duty cooler option for extended hard use.
How is it setup? Im curious. Is it like coolant hoses running though the thing or...?
 
I don't know about what hoses it would have, but I've heard that the fill plug is replaced with the temp sensor.

bdcardinal - I'd love to see any pictures you can get.
 
I have the pictures from the parts catalog. Once I get home I will post them here. The warranty return part is in front of me, give me a bit and I will take some pics for everyone.

I took a sick/mental health day yesterday so I am almost caught up.
 
Because the CHP Police Interceptor Utility has the PTU cooler, there's a temperature sensor as well. If you had access to a scantool there should be a PID or data point for that temp sensor and you could monitor the temperature of the PTU - but granted that's with the cooler, so it'll be noticeably cooler than the non-cooled PTUs.
 
Snapped these pics after work. The smell of the fluid was absolutely horrible. The consistency looked like a gas station off brand oil run in a diesel truck for 20K+ miles.







 
Here are the related parts diagrams. The system runs coolant through the cooler like the engine oil coolers.



The hose with the triangle is the water line that goes in and out of the PTU. It eventually connects to the lower radiator hose on one end and into the radiator on the other.

 
So they send engine coolant all the way back there? Wow. And the gear oil still friend like Crisco.

That system has got to hit over 300F without a cooler. Even with it seems.

Am I right in saying that we're seeing heat oxidation here?
 
That's kinda what I figured it was, running coolant against it or something.
Gawd, thats incredible! Its still cooking the fluid! What a [censored] time bomb!
 
Originally Posted By: DoubleWasp
So they send engine coolant all the way back there? Wow. And the gear oil still friend like Crisco.

That system has got to hit over 300F without a cooler. Even with it seems.

Am I right in saying that we're seeing heat oxidation here?

Well, the CHP is going to be running them a lot harder than Joe blow is going to be able to. They have to chase all those LA area runners that I watch on YouTube 3 hours after the fact.
So, its probably more of they are running just as hot as one in more normal service.
Which is still way too hot.
 
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The CHP run their cars very hard. We used to do tons of diff rebuilds on the Crown Vics because they would slam the e-brake instead of the regular brake to spin a car around. This would lock up the rear and break axles. They did the e-brake thing because it would not turn on the brake lights.

On the good side, they are fairly proactive when it comes to maintaining their vehicles. Spark plug changes at 60K, transmission fluid changes at 30k, brake fluid is flushed with fresh DOT 4 after any pursuit.

The fluid that was still left in the bag that had leaked out was very watery. Knowing it was originally a 75W140 and sheared down to that is rather scary and alarming that there is no regular service interval.
 
52B.png

Now I want to know what this does. I see you looked up those diagrams by VIN. Unfortunately I don't happen to have the VIN of a EcoBoost Utility with this $2700 option on hand.

"Not needed for day to day patrol usage."
Ford, I think people who are driving back and forth to work in SHOs and Ex Sports need this cooler.
 
Originally Posted By: Colt45ws
52B.png

Now I want to know what this does. I see you looked up those diagrams by VIN. Unfortunately I don't happen to have the VIN of a EcoBoost Utility with this $2700 option on hand.

"Not needed for day to day patrol usage."
Ford, I think people who are driving back and forth to work in SHOs and Ex Sports need this cooler.


The one we did the PTU on did not have an EcoBoost engine. We only found it was bad because we were doing both the mani-cats.
 
Originally Posted By: bdcardinal

The one we did the PTU on did not have an EcoBoost engine. We only found it was bad because we were doing both the mani-cats.

Yeah, I know. It was more a comment on how it doesn't look like that cooler is doing the business and its behind an engine with less power.
 
Originally Posted By: Colt45ws
Originally Posted By: bdcardinal

The one we did the PTU on did not have an EcoBoost engine. We only found it was bad because we were doing both the mani-cats.

Yeah, I know. It was more a comment on how it doesn't look like that cooler is doing the business and its behind an engine with less power.


Ya that cooler should be the base model while police models should have a much larger cooler similar to the Track Pack GT500 with the differential radiator up front.
 
Originally Posted By: bdcardinal
Originally Posted By: Colt45ws
Originally Posted By: bdcardinal

The one we did the PTU on did not have an EcoBoost engine. We only found it was bad because we were doing both the mani-cats.

Yeah, I know. It was more a comment on how it doesn't look like that cooler is doing the business and its behind an engine with less power.


Ya that cooler should be the base model while police models should have a much larger cooler similar to the Track Pack GT500 with the differential radiator up front.

That's what Im wondering if that's what they've done with 52B. It certainly is expensive. Part of that is going to be low volume. But, I don't think they could do anything more with trying to run coolant by it. I really suspect it is some sort of pump with a dedicated radiator.
Oh, also, I was thinking if anyone wanted to test the cat-heating theory and had an IR gun, they could let the car idle for an hour or more from a cold start and see how much heat the thing has absorbed just sitting static with hot cats next to it.
It'll cost a few dollars in fuel, but, its for science.
Just don't take your eyes off it. I don't want to watch a police chase of a stolen SHO that gets wrapped around a tree at 130.
 
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Originally Posted By: metroplex
The Middle East and Australia are probably considered "severe duty" regions, hence the drain plug.


Australian Mazda CX-9's don't have a drain plug in the PTU. I changed the oil in mine twice using a vacuum pump. Great car, but the fear of PTU failure made the decision to trade it very easy...
 
metroplex, I'll try again to answer your original question. The factory Motorcraft 75W-140 has a flash point of 375°F and that is likely the reason that the fluid eventually turns to sludge. It just cannot handle the localized heat between the gears and oxidizes.

Now a fluid like Amsoil's 75W-140 has a flash point of 410°F, so it has some cushion against the heat. Taking that a step further, Schaeffer's #170 75W-140 has a flash point of 489°F so that might be the answer to the question of what fluid is the best for the PTU. It's just hard to find it in a store or distributor. HTH.
 
I have some Redline 75W-140 lying around the garage from a previous project. I checked and the flash point is 440F, not as big of a cushion as 489F but Schaeffer's is indeed hard to find.
 
Schaeffer's #170 is PAO; no way the flash point is that high.

The technical data sheet mentioned ASTM D92, but then has an asterisk with no further explanation given.

Thermo-oxidative stability is what we're after here, and once again, I'll stress that esters are the way to go for this application.
 
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