PTU failure stories

[Junkyard_Mad-Scientist]

Share your PTU failure stories, What sounds it made, what you felt in the car, I know about the propane smell but I want to know what else to expect of she decides to let go. I have a 30 mile commute and I have had mine parked in fear of catastrophic failure and adding a tow bill to the ptu budget, but I am curious to know what the warning signs are right before it pops.

 

[SM105K]

I will post what I posed in the other thread here, so people can understand why these parts fail.

PTU! Understanding why it fails and ways to prevent failure.

Yes that thing. Here is a very good explanation by a member on here named Mr.HighCaliber.


"PTU's don't fail at least not from a power handling perspective. These only fail from lack of maintenance. Spun bearings and galling of the gears from lack of lubrication.

High Heat dries up the lighter oil molecules in the ****, which causes more heat due to lack of lubrication (thermal runaway) which leads to the remaining gear oil turning to thick black paste which clogs up the vent tube in the ptu which cause pressure buildup in the ptu which forces the remaining, non-congealed fluid out past the shaft seals. Now the only left is a thick paste thats easily flung off of the gears, sticking only to the case. After this chain of events, the bearings run dry and begin to fail, next are the gears. Tolerances widen or things begin to sieze. Bearing and gear noise are usually the first signs of mechanical failure.

But the PTU internals are stout. The weakest part of our powertrain is the RDU Atc coupler. (The electronic coupler in the rear differential). At least in terms of tq capacity and power handling."

 

[Junkyard_Mad-Scientist]

I will post what I posed in the other thread here, so people can understand why these parts fail.

PTU! Understanding why it fails and ways to prevent failure.

Yes that thing. Here is a very good explanation by a member on here named Mr.HighCaliber.


"PTU's don't fail at least not from a power handling perspective. These only fail from lack of maintenance. Spun bearings and galling of the gears from lack of lubrication.

High Heat dries up the lighter oil molecules in the ****, which causes more heat due to lack of lubrication (thermal runaway) which leads to the remaining gear oil turning to thick black paste which clogs up the vent tube in the ptu which cause pressure buildup in the ptu which forces the remaining, non-congealed fluid out past the shaft seals. Now the only left is a thick paste thats easily flung off of the gears, sticking only to the case. After this chain of events, the bearings run dry and begin to fail, next are the gears. Tolerances widen or things begin to sieze. Bearing and gear noise are usually the first signs of mechanical failure.

But the PTU internals are stout. The weakest part of our powertrain is the RDU Atc coupler. (The electronic coupler in the rear differential). At least in terms of tq capacity and power handling."

how would one diagnose the coupler? I would just let it be my ptu failing if there wasnt a little doubt. my ear hears drivetrain, like a gravely inconsistent noise, it comes and goes depending on throttle, coasting its about 80% consistent, slight throttle it comes and goes, half to full I cant hear anything but I can hear that easing into the throttle it seems to go away with more torque being added. its a quiet sound, I can hear it with the radio on low but if i turn it up it drowns it out as does high rpm engine noise. I just get the feeling its something else, maybe wishful but the noise isnt consistent enough for me to be decided fully, then again Ive never had to deal with one failing.

 

[SHOrod]

For me, the failing PTU announced itself by communicating via dolphin sounds when driving after several hours of sitting. No clunks, propane smell, or other driveline concerns, only my "chipper dolphin" sound.

-Rod

 

[SM105K]

how would one diagnose the coupler? I would just let it be my ptu failing if there wasnt a little doubt. my ear hears drivetrain, like a gravely inconsistent noise, it comes and goes depending on throttle, coasting its about 80% consistent, slight throttle it comes and goes, half to full I cant hear anything but I can hear that easing into the throttle it seems to go away with more torque being added. its a quiet sound, I can hear it with the radio on low but if i turn it up it drowns it out as does high rpm engine noise. I just get the feeling its something else, maybe wishful but the noise isnt consistent enough for me to be decided fully, then again Ive never had to deal with one failing.

The coupler will fail and you will only have FWD. From what you are saying, it sounds like the death rattle/noise of a PTU.

 

[Junkyard_Mad-Scientist]

The coupler will fail and you will only have FWD. From what you are saying, it sounds like the death rattle/noise of a PTU.

well shit, hopefully only a few more months and I can get a PTU then, was and is the plan so Ill just keep on goin.

 

[Junkyard_Mad-Scientist]

For me, the failing PTU announced itself by communicating via dolphin sounds when driving after several hours of sitting. No clunks, propane smell, or other driveline concerns, only my "chipper dolphin" sound.

-Rod

That mustve been a fun "what the **** is that" moment, mine is more of the spoon in the garbage disposal, less friendly. did you catch it or did it grenade?

 

[Austin2013SHO]

First there was a burning smell for a few weeks, had a time or two where on a fast take off it didn’t want to shift into 3rd without letting up off the gas pedal or the other great one was extremely hard down shift from 2nd to first randomly. So I removed my splash shield and got to looking at the passenger cv axel where it goes into the PTU and the seals had black peanut butter pushing out of it and after sitting for a day with no splash shield it would drip into the driveway as seen in pics.

 

[Junkyard_Mad-Scientist]

@Austin2013SHO Im scared to look under mine lol.

 

[SHOrod]

That mustve been a fun "what the **** is that" moment, mine is more of the spoon in the garbage disposal, less friendly. did you catch it or did it grenade?

It was much longer than just a moment. It made the noise for several months. I tried several times to find it and swapped/reprogrammed a used ABS pump, new PCV (since Volvos make a similar noise from the PCV system), and I think a few other things that I'm not thinking of now. I finally was able to convince myself through the use of my wireless ChassisEar that the noise was loudest from the PTU housing and decided to replace it. I disassembled the old PTU and sure enough, one of the bearings and race had turned to powder. I was honestly surprised how long it seemed to work fine, and that it didn't make more violent noises.

-Rod

 

[yaycandy]

Theres pictures somewhere down the thread of when i took the ptu out and tore it apart.

Something broke today

Just normally driving home today and started hearing a weird rattle. One i wasnt used to hearing. Intake and exhaust already rattles. Started smelling gear oil. Pulled over and popped the hood. Checked the transmission and it was still full and red. Smelled alot of gear oil with hood open...

shoforum.com

 

[Tbird6]

You have not said if the fluid has been changed? How many times and at what mileage?

As posted above that is the entire key to making things last.
With proper maintenance I would keep driving the car. If you have not changed fluid well good luck!
.
.
.

 

[Austin2013SHO]

Crazy part with mine I had purchased the car from a ford dealership and owned it for less that 6 months and this happened. They also sold it to me stuck in an Ortiz 93 tune which they had no idea and flashed back to stock so I could then retune it with gear head. I have a video of mine but it won’t allow me to upload it, the insides had this horrific smelling Burnt grease that had the consistency of gray peanut butter, it lingered for weeks after.

 

[Junkyard_Mad-Scientist]

You have not said if the fluid has been changed? How many times and at what mileage?

As posted above that is the entire key to making things last.
With proper maintenance I would keep driving the car. If you have not changed fluid well good luck!
.
.
.

I changed my fluid a few months after I bought it and switched it LWSP and changed it again about 20k after that, just before that is when it started making the noise.

 

[LilCop2002]

First there was a burning smell for a few weeks, had a time or two where on a fast take off it didn’t want to shift into 3rd without letting up off the gas pedal or the other great one was extremely hard down shift from 2nd to first randomly. So I removed my splash shield and got to looking at the passenger cv axel where it goes into the PTU and the seals had black peanut butter pushing out of it and after sitting for a day with no splash shield it would drip into the driveway as seen in pics.

This is what mine did.