2008 AWD rumble//slight grinding noise from front end // Transfer case or pto issue??

[2008mkzawddeargodplzhlp]

Let me start off by saying that I've never owned a vehicle that I could not find information on. I've had a handful of Expeditions, escapes and town cars ranging from 1998-2014 and none of them have been difficult to find info on like my current project, the 2008 Mkz AWD.

Now presumably you have all heard questions about the transfer cases on these things because that's what everyone has been saying but Nobody can go into detail lol.

I have a 2008 mkz awd. I picked it up for super cheap and intend on maintaining it for as long as my patience lasts lmao.

Its shifts smoother than most vehicles at 190k doesnt shift early or late but there is a whirring sound that comes from the engine bay/front of car mostly during heavier acceleration and when the car bounces a bit on wonky roads. It almost sounds like a modified exhaust but the fact that it's coming from the engine may makes me feel like it's actually a whirring coming from a slight grinding of sorts.

Now I've read a fair bit about these transfer cases and how they need to be serviced even though theres no drain plug and Ford said they wouldn't need to be.

I'd LOVE to check the fluid on it but I cant figure out how to accurately judge what is FULL or LOW without removing it entirely. I've dived into this site and the forums a bit and found other posts referring to a similar noise but they're all abandoned posts.

If you can not help me find one maybe we can make this into one for others to help themselves.


Transfer case fill hole location?
Any info on the mythical self tapped drain plug?
Transfer case oil type?

[Viking]

For the rumbling and vibration, check the driveshaft.  Good chance that is your problem there.  On the whining, it is possible it is a combination of the A/C pump drawing enough of the engine torque to affect the alternator's attempts to recharge the tiny battery.  So the alternator whines a bit.  On the first, you would have a toss up on the transfer cast or the driveshaft as to which is more expensive and painful to fix.  The driveshaft is expensive, not serviceable, but easy to change, while the transfer case is serviceable, but a real pain. 

 

The transfer case drain hole is on the right side lower case, and the fill hole above and to the rear of that.  I do not know anything about the mythical self tapped drain plug.  The transfer case uses 75W90 gear lube.  The transfer case, by the way is known as a PTU or Power Transfer Unit in these cars.

Edited February 24, 2021 by Viking

[2008mkzawddeargodplzhlp]

3 hours ago, Viking said:

For the rumbling and vibration, check the driveshaft.  Good chance that is your problem there.  On the whining, it is possible it is a combination of the A/C pump drawing enough of the engine torque to affect the alternator's attempts to recharge the tiny battery.  So the alternator whines a bit.  On the first, you would have a toss up on the transfer cast or the driveshaft as to which is more expensive and painful to fix.  The driveshaft is expensive, not serviceable, but easy to change, while the transfer case is serviceable, but a real pain. 

 

The transfer case drain hole is on the right side lower case, and the fill hole above and to the rear of that.  I do not know anything about the mythical self tapped drain plug.  The transfer case uses 75W90 gear lube.  The transfer case, by the way is known as a PTU or Power Transfer Unit in these cars.

 

 

Thank you SO MUCH for the reply. I'm going to check the driveshaft first. 

 

Can you tell me where to locate the PTU? I've seen videos of similar model fords but I cant find it on my mkz.

 

I've noticed as of lately that the vibration//rumble//slight grinding happens prominently when it's cold or wet outside but on warmer dryer days like today, it's almost non existent. 

 

 

 

 

[drolds1]

Here's a video that will show you where the PTU is and how to change the fluid.  Brian Makuluoco is considered the Ford guru around here and elsewhere in the Blue Oval world.

 

If this doesn't help, just follow the driveshaft to the front of the car and see where it's attached to the flange on the output side of the PTU.

[2008mkzawddeargodplzhlp]

Update: I'm noticing now that it doesnt happen when my steering is right of dead center . Also if begin to accelerate while steering to the right and slowly straighten out  it doesnt happen either. 

 

If it's only happening with weight distribution and steering what could it be? 

Edited February 25, 2021 by 2008mkzawddeargodplzhlp

[Robert Iggy Cerami]

Having the PTU replaced on my 2020 3.0  14950 miles... started a slight vibration and rumble a few weeks ago.. not my first MKZ so I knew something was not right... I thought it was a motor mount at first, but dealer test drove and they came the conclusion that it was the PTU .. part was ordered and should have my car back Monday .. Wanted to know if there would be a break in period for the PTU or can I just drive normally ?

[bbf2530]

2 hours ago, Robert Iggy Cerami said:

Having the PTU replaced on my 2020 3.0  14950 miles... started a slight vibration and rumble a few weeks ago.. not my first MKZ so I knew something was not right... I thought it was a motor mount at first, but dealer test drove and they came the conclusion that it was the PTU .. part was ordered and should have my car back Monday .. Wanted to know if there would be a break in period for the PTU or can I just drive normally ?

 

Hi Robert. Well, it all depends on what you consider to be "normal". If driving aggressively/hard is normal for you, then no, don't do that.

 

Although we are not sure exactly all of what is being replaced, there is the chance there will be broken-in parts and pieces interacting with new parts and pieces.

Therefore, this is what I would recommend: Although it may be difficult, my advice would be to drive the car the same way Lincoln recommends it be driven when new. "Easy" (simply meaning normal, not hard) for the first 1,000 miles. Might that be a bit of overkill? Yes possibly. But why take the chance.

 

Obviously, it would not hurt to also ask the tech what his advice is. But either way, I would advise normal, non-aggressive driving for at least several hundred miles. With 14,950 miles already, that should not take long for you. ?

 

Let us know how you make out and good luck.

Edited February 25, 2021 by bbf2530

[drolds1]

7 hours ago, 2008mkzawddeargodplzhlp said:

Update: I'm noticing now that it doesnt happen when my steering is right of dead center . Also if begin to accelerate while steering to the right and slowly straighten out  it doesnt happen either. 

 

If it's only happening with weight distribution and steering what could it be? 

Check wheel bearings.

[2008mkzawddeargodplzhlp]

3 hours ago, drolds1 said:

Check wheel bearings.

 

So I did a quick shake test to both front wheels today and there was no play. When I get a chance I'm going to pull them off and further inspect them.

 

I have a question or two regarding the common ptu failures..

 

1.What are the common symptoms of ptu failures on these vehicles? ( I've read clunking, grinding and smell but I'm only experiencing a grinding)

 

2. If my ptu was shot, would I be able to accelerate at all without the grinding? It seems to me like the grinding would he constant during all acceleration..

 

 

[2008mkzawddeargodplzhlp]

I know nobody is looking at this anymore but in case someone comes across this in the future. 

 

The symptoms were a

Originally coming and going with the temperature outside. 

 

The last few days have been beautiful and the symptoms are gone.

 

If they come back, I will revisit and update.

As of now, this is the last post.

[bbf2530]

Hi 2008MKZ. Members are looking and reading. Sometimes there just is no answer or way to accurately diagnose over the Internet, other than blind Internet speculating, even for our tech members.

 

Thanks for the updates though. They may help others in the future.

 

Good luck.

Edited March 2, 2021 by bbf2530

[Robert Iggy Cerami]

On 2/25/2021 at 12:58 PM, bbf2530 said:

 

Hi Robert. Well, it all depends on what you consider to be "normal". If driving aggressively/hard is normal for you, then no, don't do that.

 

Although we are not sure exactly all of what is being replaced, there is the chance there will be broken-in parts and pieces interacting with new parts and pieces.

Therefore, this is what I would recommend: Although it may be difficult, my advice would be to drive the car the same way Lincoln recommends it be driven when new. "Easy" (simply meaning normal, not hard) for the first 1,000 miles. Might that be a bit of overkill? Yes possibly. But why take the chance.

 

Obviously, it would not hurt to also ask the tech what his advice is. But either way, I would advise normal, non-aggressive driving for at least several hundred miles. With 14,950 miles already, that should not take long for you. ?

 

Let us know how you make out and good luck.

Finally got my car back.. they  found metal contamination in the PTU fluid.. They ordered and replaced it.. no break in required, but as you suggested I will take it easy for a bit.. Thank you

[bbf2530]

35 minutes ago, Robert Iggy Cerami said:

Finally got my car back.. they  found metal contamination in the PTU fluid.. They ordered and replaced it.. no break in required, but as you suggested I will take it easy for a bit.. Thank you

 

Hi Robert. You are very welcome. Happy to hear they were able to properly diagnose and fix it.

 

Good luck. ?

Edited March 4, 2021 by bbf2530

[jdmancus]

I have an 08AWD which I purchased last Nov. Appreciate the updates on the vehicle.