PTU Problems

[ExPlat]

Thanks for that ExPlat. I wasn't aware that there were vehicle messages for that.
Change 4WD Transfer Unit Lube and
4WD Power Transfer Unit Lube Set to New
Peter

LOL, it doesn't matter how many times I read the Owners Manual, there always seems to be a surprise in it. That little blurb was hidden in the 'Scheduled Maintenance: Exceptions: Axle Maintenance, page 492 of the 2016 OM.
http://www.explorerforum.com/forums...r-diff-fluid-change-2011-explorer-xlt.446413/
(We did discuss this a year ago on another thread but things get buried in the sheer volume of posts on this busy website.)

 

[Irishfred]

I hope that the quantity of fluid has changed (from the 17oz or so from the prior version)? Is this only in the PI version, and not the normal garden-variety 4WD Explorers? Does this unit also have the cooler addition (which would mean more volume of oil)? If the answer is a recurrent yes, then your longevity should be much better than the 2012 vintage PTU.

It's funny that Ford really wants to keep that Transfer Case "maintenance free" with anti-tamper paint. I wonder if there is a temperature sensor vs level sensor in the unit. Good for Ford for addressing this issue.

A quick look over at the Toyota forums has the Highlander transfer case with a drain plug, approx 32oz of fluid, and what appears to be heatsinks built into the case. Those Toyotas are simply bulletproof for a reason - they are designed to stay on the road forever. They have recommendations to change the transfer case every 15k miles if towing, otherwise check every 30k for routine maintenance. Many of their fans on that site are DIY changing with amsoil at 100k miles to keep them going strong...

 

[KayGee]

I hope that the quantity of fluid has changed (from the 17oz or so from the prior version)? Is this only in the PI version, and not the normal garden-variety 4WD Explorers? Does this unit also have the cooler addition (which would mean more volume of oil)? If the answer is a recurrent yes, then your longevity should be much better than the 2012 vintage PTU.

Not sure if that applies to Retail Explorers and PIUs. I think the cooler just runs coolant to the PTU - no added PTU fluid capacity in the PTU.

If you read the above changes I posted, it looks like the improvement to 2X life of original PTU happened in Oct 2015 which is basically 2016 model year and then the 3-4X life improvement (which I believe yields the 8X more durable than the original PTU comment) didn't happen until June 2016 which is the end of the 2016 model year - basically just in time for the 2017 model year. Only time will tell how well 2016s do with higher miles (60-100K+) and then how well 2017s do with the same higher mileage (might be a little while until they get up to 60-100K+ miles) vs. 2015 and earlier models.

 

[peterk9]

I hope that the quantity of fluid has changed (from the 17oz or so from the prior version)? Is this only in the PI version, and not the normal garden-variety 4WD Explorers? .............

The previous post #340 applies to the Explorer since the notes are from the Explorer Owner's Manual. I don't know if the PIU has its own Manual or not.

Peter

 

[ExPlat]

Not sure if that applies to Retail Explorers and PIUs. I think the cooler just runs coolant to the PTU - no added PTU fluid capacity in the PTU.
If you read the above changes I posted, it looks like the improvement to 2X life of original PTU happened in Oct 2015 which is basically 2016 model year and then the 3-4X life improvement (which I believe yields the 8X more durable than the original PTU comment) didn't happen until June 2016 which is the end of the 2016 model year - basically just in time for the 2017 model year. Only time will tell how well 2016s do with higher miles (60-100K+) and then how well 2017s do with the same higher mileage (might be a little while until they get up to 60-100K+ miles) vs. 2015 and earlier models.

Unfortunately my 2016 was built on 03/08/2015 and probably has the 2014 PTU with a FFTW. It does have the Tow package so a coolant radiator is supposed to be installed but I haven't looked to see if it is actually there. Here's a diagram on how that PTU cooler is plumbed:

PTU cooler diagram copy.jpeg

 

[KayGee]

Unfortunately my 2016 was built on 03/08/2015 and probably has the 2014 PTU with a FFTW. It does have the Tow package so a coolant radiator is supposed to be installed but I haven't looked to see if it is actually there. Here's a diagram on how that PTU cooler is plumbed:

My 2016 was built on 9/25/15 and presumably just missed the 2x improved PTU also - has part #DG1Z-7251-D - which is the same part number listed for 2016 platinum PTU with cooler/tow package. I'll have to get underneath and take a look to see if mine really has the aux PTU cooler as it did not have that option listed.

My 2017 PTU is part # DG1Z-7251-F. When I entered DG1Z-7251-E, it shows that it was from 6/8/16, but was superseded to DG1Z-7251-F. Not sure why the older PTUs are still available, but maybe the June 2016 change in the PTU is not backwards compatible with older models. If I were replacing a bad PTU, I'm not sure I'd want to put the same one back in - I would want the one with the latest improvements.

 

[whimsey]

Our 2017 4 WD was built in Oct 2016, the OM states that the PTU quantity is 700 ml or about 23.68 oz. It states in the OM that the PTU and rear axle are non maintenance items BUT for "certain" conditions change the fluids in them every 30,000 miles. The transmission is to be changed every 150,000 miles BUT under the same "certain" conditions change that every 30,000 miles.

Whimsey

 

[Irishfred]

The problem -

This 4x4 module will engage the transfer case during acceleration if the vehicle has sets of tires with different circumferences.

When the circumferences of the tires are not the same it causes the 4x4 module to believe a slipping condition is present and engage the transfer case.

The continual engagement of the transfer case results in load on the contained oil. The 17 oz of oil next to the exhaust system will not last long under these conditions in this Ford.

The dealer will likely not tell you this (they did not tell me anything - and even checked it as OK without filling the oil reservoir 4k miles ago).

Eventually, they will offer you a replacement for $2k as the remedy once it fails.

Rotate tires every 5-7k miles, and avoid any discrepancy between tires on your car, is my advice.

And find a competent mechanic that knows this issue if you own a 4wd unit.

 

[KayGee]

The problem -

This 4x4 module will engage the transfer case during acceleration if the vehicle has sets of tires with different circumferences.

When the circumferences of the tires are not the same it causes the 4x4 module to believe a slipping condition is present and engage the transfer case.

The continual engagement of the transfer case results in load on the contained oil. The 17 oz of oil next to the exhaust system will not last long under these conditions in this Ford.

The dealer will likely not tell you this (they did not tell me anything - and even checked it as OK without filling the oil reservoir 4k miles ago).

Eventually, they will offer you a replacement for $2k as the remedy once it fails.

Rotate tires every 5-7k miles, and avoid any discrepancy between tires on your car, is my advice.

And find a competent mechanic that knows this issue if you own a 4wd unit.

Every AWD vehicle is different and the difference in circumference can vary from what is acceptable to unacceptable. I haven't seen anything specific for the Explorers, but I have seen other AWD vehicles that specify a variance of less than 1/2" in circumference for all tires of the AWD system isn't adversely affected.

My opinion is that the vehicle is programmed to send at least some power to the rear wheels almost all the time and the PTU is pretty much always working. Substantial tire circumference differences certainly don't help, but I doubt they are changing the operation of the PTU much.

I haven't driven with Forscan running and recording to confirm, but if the AWD gauge in the dash is to be believed, both of my PIUs send power to the rear wheels a lot. Under acceleration, mine send anywhere from maybe 25% to almost 100% power to the rear wheels. Any time I am driving a steady speed it does favor the fronts, but as soon as the gas pedal is moved at all, it immediately begins shifting power to the rears. My AWD gauge constantly bounces around from ~100% front to ~100% rear, and everywhere in between. Conditions so far have been dry or rain - waiting to see how it operates in snow.

 

[Irishfred]

Here's my opinion.

I am certain that this is the underlying problem with this PTU.

The variability of failure in this unit, which in design is simple (albeit fatally flawed in terms of lubrication volume) points directly to this tire circumference theory.

There is no other practical explanation for this issue. If it were heat from the exhaust, then the failure would be in accordance from those that are driving long distances. In addition, it would occur in the first 10000 miles of ownership - especially for those who are driving long distances.

This is simply not the case - because the tires have not worn down during this interval to pose a problem...

When this problem reared it's head in my case, was near the end of my tire's lifespan. I did not rotate the tires as I needed to in this fragile scenario. That's when oil began to boil out, stick to the undercarriage to the car, then drip down to the garage floor.

Ford says that this is a non-maintenance / lifetime item. They are correct - as long as you rotate your tires every 5-7k miles.


In my particular case, I caught the problem in time and saved the case. There appears to be no bearing damage nor noise, and I flushed the sludge with a solvent of petroleum fuel oil. I then added a superior crankcase oil than what is recommended by Ford - specifically one with the highest boiling point that I could find. I now know what to look for, and expect that with faithful tire rotations this will no longer be a problem.

I'll let you all know how this works out, and if any more oil is boiling out after the fresh set of tires and the new AMSoil oil...

 

[peterk9]

I think the PTU on a PIU is set up differently. I've never noticed 100% to the rears. Tried a 'jack rabbit start' in my 2011 and managed about 75% to the rear. Haven't attempted it with my Ecoboost.

Peter

 

[KayGee]

@Irishfred
How many miles did you go without rotating tires?

What was the variance in circumference/tread depth from front to rear tires in your case?

 

[KayGee]

I think the PTU on a PIU is set up differently. I've never noticed 100% to the rears. Tried a 'jack rabbit start' in my 2011 and managed about 75% to the rear. Haven't attempted it with my Ecoboost.

Peter

It was hard to tell exactly what the split was, but it was like 1 bar front and all the rest to rear. I think 75%+ is a lot to put through a dinky ptu and smallish propshaft (compared to the driveshaft that a primary rear driver would have) - especially if it happens with any frequency.

 

[blwnsmoke]

Here's my opinion.

I am certain that this is the underlying problem with this PTU.

The variability of failure in this unit, which in design is simple (albeit fatally flawed in terms of lubrication volume) points directly to this tire circumference theory.

There is no other practical explanation for this issue. If it were heat from the exhaust, then the failure would be in accordance from those that are driving long distances. In addition, it would occur in the first 10000 miles of ownership - especially for those who are driving long distances.

This is simply not the case - because the tires have not worn down during this interval to pose a problem...

When this problem reared it's head in my case, was near the end of my tire's lifespan. I did not rotate the tires as I needed to in this fragile scenario. That's when oil began to boil out, stick to the undercarriage to the car, then drip down to the garage floor.

Ford says that this is a non-maintenance / lifetime item. They are correct - as long as you rotate your tires every 5-7k miles.


In my particular case, I caught the problem in time and saved the case. There appears to be no bearing damage nor noise, and I flushed the sludge with a solvent of petroleum fuel oil. I then added a superior crankcase oil than what is recommended by Ford - specifically one with the highest boiling point that I could find. I now know what to look for, and expect that with faithful tire rotations this will no longer be a problem.

I'll let you all know how this works out, and if any more oil is boiling out after the fresh set of tires and the new AMSoil oil...

Almost 118k on mine now, 3rd set of tires.. got about 59k on the 1st set, 53k if I recall on the 2nd set. Never rotated my tires ever. Original PTU. Just did my first out of pocket expense (besides oil changes and brakes).. changed coolant Thursday and replaced upper right strut mount.

I don't rotate on my Camry or my f350 either.

Don't get me wrong, I am hoping my PTU dies blow so I can replace it under warranty BUT so far, no leaks, drips or fluid disappearing anywhere.

 

[Irishfred]

https://www.mazdas247.com/forum/sho...Changing-CX-9-transfer-case-gear-oil-(photos)

The Mazda guys have figured this issue out, and have been on it for years. The above thread is thorough and invaluable. I followed their lead on this process, and saved the PTU from certain death.

Good luck to those who are betting on the "maintenance free" line. After seeing the fluid for yourself - the consistency and the smell as compared to the original fluid - there is no doubt that maintenance is the way to go if you are not leasing this thing.

Some feel that the motorcraft fluid is partly to blame for the fast degradation. Leaving nothing to chance, I went with AmsOil without any additives.

Thanks to all on this forum for your opinions and input. I'm glad to be aware of this issue now and foresee no further issues (despite having to service the PTU on every other oil change).

I rotated my tires every 15k prior to this issue - with this new PTU oil schedule, I will rotate my tires every 7k (while I shop at Costco).

I'll post the results of this intervention, and let you all know how it goes from this point onward!

 

[Odrapnew]

I changed my Sport's PTU fluid at about 60k miles and had a oil analysis completed on it. The report said the fluid was more representative of 30k miles. When I drained it, it didn't look terrible. It was darker than clean fluid, but not by much and it still flowed like fluid. Definitely not as bad as some people indicate.

Oh, and I don't believe the lifetime fluid hype either. I'll probably change it again in another 40k miles.

 

[Irishfred]

I changed my Sport's PTU fluid at about 60k miles and had a oil analysis completed on it. The report said the fluid was more representative of 30k miles. When I drained it, it didn't look terrible. It was darker than clean fluid, but not by much and it still flowed like fluid. Definitely not as bad as some people indicate.

Oh, and I don't believe the lifetime fluid hype either. I'll probably change it again in another 40k miles.

Outstanding!

Glad to hear. I wonder if they changed the design from the 2012 (which is what I had).

While tackling this job, and referencing the thread that I posted above, my personal thought was how Ford could have designed this unit and slept at night. The smell of this fluid alone is enough warning that things will go bad without any intervention.

In my case, after a few flushes, the toothpaste-like "lifetime oil" thinned out to something that resembled what you described in your post.

Best of luck!

 

[peterk9]

Outstanding!

Glad to hear. I wonder if they changed the design from the 2012 (which is what I had).

http://www.explorerforum.com/forums/index.php?threads/ptu-problems.379087/page-14#post-3653471

 

[Odrapnew]

One other comment. My wife has a 2009 CX9 and I changed her PTU fluid at about 120k miles. That fluid was black. It was still fluid(ish), but it was not pretty. About 15k miles later, it started to leak and the PTU was replaced at that time. From what I’ve read, the new fluid may have “cleaned” out some of the gunk around the seals which created a leak path. It wasn’t a massive leak, but it would leave a few drops overnight.

I think 50k mile change intervals would be reasonable. If you can do it yourself, it's an hour or 2 of work and less than $10, even with the good stuff. I picked up the Amsoil stuff for about $15 a bottle and still have just over half left.

 

[Irishfred]

One other comment. My wife has a 2009 CX9 and I changed her PTU fluid at about 120k miles. That fluid was black. It was still fluid(ish), but it was not pretty. About 15k miles later, it started to leak and the PTU was replaced at that time. From what I’ve read, the new fluid may have “cleaned” out some of the gunk around the seals which created a leak path. It wasn’t a massive leak, but it would leave a few drops overnight.

I think 50k mile change intervals would be reasonable. If you can do it yourself, it's an hour or 2 of work and less than $10, even with the good stuff. I picked up the Amsoil stuff for about $15 a bottle and still have just over half left.

Did your fluid look like this?