Buzz in Park and Neutral - '95 MK VIII

dRock95MarkVIII

dRock95MarkVIII

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Hey everyone, got a question -

My Mark has been wonderful, however out of no where there was a buzzing/rattle type sound from the back of right front wheel area when I started it about an hour ago tonight.
This is the first time the noise has appeared, and semingly for no reason at all.

THe noise is only present in Park and Neutral, no noise in gear.

The noise gets much quieter, and eventually is gone at idle as the engine/fluids/exhaust warms up. However it will make the sound again if I blip the throttle (again, P/N only)


I'm pretty well-versed in panther platform tech, so my first thought was heat shields on the cats buzzing/rattling. My Mark is so damn low there was no way for me to check them out or look tonight, but I will probably put some hose clamps around them just in case to rule them out.


I've heard a buzz from the valve body can occur on the -95s - I'm not sure if this is what I have. It occurs only in park and neutral, gets quieter when warm and car operates flawlessly. The buzz is not very consistent, goes in and out and sounds VERY tinny. The buzz matches engine RPMs, however, once the car warms up just a little bit it only occurs when the throttle is being pressed (meaning, if I rev the engine up I will hear the buzz match RPMs, but the second I release the throttle the noise is gone - even if the engine RPMs have not dropped fast enough yet)


Is it normal for the valve body buzz to appear out of no where? The car was dead silent just yesterday - the noise *just* started today.


Any thoughts would be much appreciated :)
 
Oops, didn't read your thread completely, had a brain fart, you mentioned the heat shields, sorry.:D :rolleyes:
 
My Thought (Just a thought)

Is could be exhaust related since your noise is at the rear of the car. There is nothing really back that far to point a finger at other then a muffler and fuel tank. You can stuff rags in your tailpipes and start the car to get a better since of where the noise is coming from. Just a thought. Good Luck.
 
Thanks :)


There is no noise from the back of the car, it is right around the center, most noticeable from the rear of the FRONT right wheel.


Anyone have a good description of the valve body buzz?

I'm going to put the clamps on the shields and I guess I'll see where it goes from there.
 
Well, I'm pretty sure what I have right now is valve body buzz. For me though, it's not noticeable at all unless I put my foot on the gas a little while in Park. It's just barely noticeable in Neutral or Drive just after I start putting the gas down, but goes away almost immediately after I start hearing it.

I haven't been able to hear the buzz from under the hood, and it's best heard from either side of the car, sounding like it's coming from underneath just a little behind the front wheels. It isn't present at idle, but once I start speeding the engine up it is audible until about 3,000 RPM which is when the sound of the engine starts to drown it out. It goes away right when I let off the gas even before the tach starts to drop.

Another accompanying issue is a late WOT shift from 1-2, but I'm not sure whether that's 100% related. It's up to you if you want to test it on yours, but I wouldn't recommend it. The tachometer gets to about 6500 RPM before my car will shift in WOT.

Hope this helps. I've got another topic in this forum on my issue, entitled "Engine Buzzing" or something like that, if you want to look at it.
 
Iszi, your issue sounds very similar to mine.

After reading your posts though, some things I noticed different where that your's is quiet at idle - I can hear the buzz at idle. You can hear the noise when accelerating, I cannot, the noise is gone the second the car goes in gear - only happens in N and Drive.


BTW, your late 1-2 shift issue sounds typical of the old-style aluminum 1-2 shift accumulator o-ring/bore wear.
Check out this link:
http://www.p71interceptor.com/tranny/accumulators/partnumbers.html



I installed hose-clamps on the two upstream cats, and I diagnosed the sound a little more. The hose clamps seemed to make no difference, so I can rule that out.

And to add to my exisiting statement:
I've heard a buzz from the valve body can occur on the -95s - I'm not sure if this is what I have. It occurs only in park and neutral, gets quieter when warm and car operates flawlessly. The buzz is not very consistent, goes in and out and sounds VERY tinny. The buzz matches engine RPMs, however, once the car warms up just a little bit it only occurs when the throttle is being pressed (meaning, if I rev the engine up I will hear the buzz match RPMs, but the second I release the throttle the noise is gone - even if the engine RPMs have not dropped fast enough yet)


Is it normal for the valve body buzz to appear out of no where? The car was dead silent just yesterday - the noise *just* started today.
Click to expand...
The buzz will also 'pop' in and out rapdily at times, please try not to laugh to hard at my attempt to demonstrate this with a keyboard lol:
buzzzzzzzzzzzzzzzzz-buzbuzbuz-buzbuz-buzzzzzz-buzbuzbuz buzzzzzzzzzzz
lol, try to um.... act that out as best you can to get an idea. I'll try and get a sound clip as well.

It sure seems odd that an issue like tis can occur out of no where - the car was silent the day before then all the sudden it happened when I started it up the next day :shrug:



BTW, after working just a little on this car, my old T-bird, and quite a bit on my Marquis - thank god for the spacious and simple layout of the panther platform - what a breeze everyhting is to work on compared to these MN12/FN10s lol.
 
Everything you're saying sounds exactly like what I had a on my 94.

From the buzzing only in park or neutral, to being very intermittent.

It had the valve body noise for 2 years until I sold it, never affected anything though; supposedly it's harmless.... yet still very annoying! :p
 
Alright, after a little more careful diagnostic driving I've also found that the car now has a buck, or stumble at around ~25mph while crusing at low throttle positions up steep inclines.

Is this just torque convertor shutter? I'm used to this occuring at higher speeds on panther platform cars.

The car had no shutter before, this is new - think it's related?


I'm going to have the trans flushed with Mercon V as soon as I can when I go get the oil changed. Think it may help with the valve body buzz some?
 
My '95 does the same thing. It's very intermittent, and I mostly hear it when the engine goes just above idle. Like when I'm creeping along in a drive-thru line, for instance. When the transmission is cold, it sounds more like a rattling heat shield. When it's warmed up, it sounds like the "bzzzzzzt" noise that most 80s-90s Chryslers make when they come to a stop.

I don't think it's related to TC shudder. I had that problem when I first bought the car. When it shifted into overdrive at 35-40 mph, it briefly felt and sounded like I was driving on a rumble strip. It went away after I changed the fluid w/ Mercon V. It didn't have any impact on the buzzing noise, though.
 
dRock95MarkVIII said:
You can hear the noise when accelerating, I cannot, the noise is gone the second the car goes in gear - only happens in N and Drive.
Click to expand...

1.) I don't recall saying that I can hear the buzz on acceleration. If I did, it was probably referring to the acceleration of engine RPM while parked.

2.) You say here your buzz only happens in Neutral and Drive, but your initial post said Park and Neutral. Typo?
 
#1 - I was reffering to this part of your thread:
Iszi said:
Up to 2,000 RPM under light engine acceleration (I'll check further when I get home) it doesn't seem to go away
Click to expand...

#2 - Yes, Park and Neutral - please excuse my typo in the later posts :oops:
 
dRock95MarkVIII said:
#1 - I was reffering to this part of your thread:


#2 - Yes, Park and Neutral - please excuse my typo in the later posts :oops:
Click to expand...

Yeah, that was referring to me speeding up the engine RPMs while in Park. That's why I said "engine acceleration" instead of just "acceleration" or "vehicle acceleration".
 
I have a similar sound. I only notice it when I'm in a drive through though.

However, I DO NOT have the sound when I'm in park or drive, just when I'm sitting at idle. Once I apply any throttle, it goes away.

I don't think it's an issue, I have a recently rebuilt transmission/brand new torque converter..
 
Calabrio said:
I only notice it when I'm in a drive through though.
Click to expand...

For me, it's hard to notice unless I'm really listening for it or the car is close to a sound-reflective surface such as a wall or another car. (i.e.: Drive-thru, or close-quarters parking.)

Calabrio said:
I have a recently rebuilt transmission/brand new torque converter..
Click to expand...

So do I.
 
I've had the same symptoms for a while. I hear it the most going along my fence and into the garage.
 
Thanks for all the replies guys, I really appreciate your help :)


What ever my issue is - it's loud. I can hear it inside the car with nothing around it. Then again, I am a bit picky when it comes to noises - my Marquis and our Town Car spoil me lol.

Now the noise doesn't show up on cold start up anymore - now it only happens once its driven a little bit and then put back in park or neutral. It's no where near as loud as the other day, though. Now at idle it's a very low, superfast buzz - almost like a modular p/s pump with cruddy fluid in it lol.

I'm going to assume this will be an intermittent issue for me. I'm just going to order a new valve body (96-00 style, 97+ accums), 96+ pan and filter.
I'm still going to get the trans flush asap anyways, can't hurt and needs to be done regardless because of the shudder.


BTW - do you guys recommend running an external OTA transmission cooler on these cars?
I know on many newer Fords, stock cooling is excellent, but I'm not sure on these. I have 2 brand new B&M supercoolers sitting in my closest (were going to be heat exchangers for my Marquis' supercharger project) and don't mind throwing one on the Mark if it will be beneficial.
 
An external transmission cooler is always recommended for our cars.

Is that buzz loud enough you can hear it with the windows up? I usually don't hear mine unless they're down.
 
At idle - When the noise is getting very loud, I can faintly hear it with the windows up - when the noise is just the quiet continuous buzz, I can't hear it with the windows up.
I can hear the noise/buzz the second I hit the accelerator windows up or down.
 
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