What are the signs the Power Transfer Unit (PTU) is failing

[Professor_Tomorrow]

My Explorer is a 2015 XLT AWD with 120,000 miles. On hard acceleration mainly going uphill there is a strange burning smell. It almost seems like bread baking at Subway.

I read that this was 'normal' smell coming from the PTU vent. It does seem to be worse when pulling a trailer. I looked at changing the gear oil, but of course mine is a sealed unit. I watched Brian at Ford Tech Makuloco demonstrate how to change it without a drain plug. It looks pretty complicated.

I'd like to just have the PTU changed out with one that has a drain and fill plug.
1. Is there and OEM Ford/Motorcraft updated PTU with a fill and drain plug? I know Dorman makes one.
2. I'm not a fan of 'fixing things that aren't broken.'
3. My concern is what indications does a failing/failed PTU present? Does it even give any signs or does it just stop working?
4. If it stops working does the vehicle become unsafe and undrivable?

Thanks,

 

[peterk9]

Several reports mention that a failing PTU will generate a propane-type or natural gas odour. You may hear grinding noises and or shuttering on take-off.
It can cause transmission damage if it seizes while driving.
I don't know if the PTUs that are now available have a drain or not.

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Peter

 

[onestout]

I just added a drain plug to my PTU....not hard, drill a hole, tap for a plug, screw in plug. A lot easier and cheaper than putting in a different PTU.

 

[BrettS.]

Usually the PTUs fail due to insufficient lubrication and the bearings inside fail. Specifically the bearing that mounts in the case which takes out the case and makes it impossible to rebuild. Find a way to regularly change the fluid or it will fail.

 

[StormTrooperExplorer]

I just added a drain plug to my PTU....not hard, drill a hole, tap for a plug, screw in plug. A lot easier and cheaper than putting in a different PTU.

Where did you drill the hole at?

 

[onestout]

there is video on youtube or this site that I went by but you can sort of figure it out just by looking at it where it needs to be. You want to drill in between the gears so you don't hit them. I think I used a 1/4" plug but you don't need one that big, just makes it a little more difficult to tap. The pics/video I found had some rough dimensions of about where to put it.....pretty sure it is on this site somewhere also.

 

[J_C]

Here's a video example, for hole location and more info about fill options.

 

[onestout]

one bit of advice since there are a lot of videos out there on how to do this....use a tapered pipe plug....do not use a straight threaded drain plug. There is no machined surface for it to seal on, you want the threads to do the sealing since you will be using a hand drill for this.

 

[J_C]

Do you think something like Permatex high temp thread sealant would be the best choice?

https://www.amazon.com/Permatex-59235-Temperature-Thread-Sealant/dp/B000AAJTYS?tag=seriouexplor-20

One thing I wondered about was putting in a valve instead, like a fumoto style often used on oil pans.

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[onestout]

not something I would ever do, stick with a tapered plug, they will give you the best seal without having to remove the ptu and machine a flat onto the outside of the case.

 

[peterk9]

Since the OP hasn't replied to any posts so far, I'd suggest he find out if the PTU is still serviceable before going ahead with any drilling for a drain plug. If the PTU is 'toast', that would be a lot of wasted effort. It seems the issue has been going on for a while.

Peter