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Discussion Starter · #1 ·
Howdy all,

I have a 2002 F-350 turbo diesel, 4x4, crew cab, long bed, dually with just over 180k miles on it (this week as it gets driven a lot)- 50% of the milage heavy towing. So far so good except for the loud fan-like noise I am now hearing and the occasional whine from underneath. I can still drag a stock Cummings like it was a trailer provided there is enough traction and drift (yes DRIFT) the truck on most corners coming home from work. /ubbthreads/images/graemlins/laugh.gif

The fan-like noise can happen warm or cold but always when asking the truck to move. Never stationary. At first I considered the cooling fan on the engine- but that should not be kicking in when it is just started up and put into motion. It is also something I can’t quite see while rolling down the road.

Sometimes, I can nearly complete a 30 mile trip and never hear the sound only to have it kick in as I start moving again at the stop sign down the street from my house. Occasionally, it seems a little hesitant to shift (only when fan sound is already present) and if I keep pushing down on the accelerator I get a terrible whine. The whine will go away as soon as I let up on the accelerator or the transmission up-shifts.

Please tell me this is a cheap fix! The truck already ate a starter, an alternator and 2 batteries this winter! All these parts were original equipment but still not easy to suck up in such a short period. I know I am doing very well for the (mileage) life I have gotten out of the transmission and the harsh treatment it has gotten throughout its pretty short life.

It is getting time for an oil change and a transmission fluid change as well due to mileage. The trans fluid is exactly at the right marks and looks as new as when I put it in, there is no sign of metal flakes in it or even any discoloration or burnt smell- Is a change of the fluid likely to even help or be about $100 wasted that I could put to an upgrade?
 

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First off,, Welcome to TDS. I know you will learn tons about your truck here. I have. I would have to guess that your fan is kicking in when it normally shouldnt..I know when MY CLUTCH fan kicks in man,,is it loud.
As far as the whine,,,I do not have a real educated guess for you on that,,,someone will soon ,, I am sure!
Again... WELCOME to TDS.
 

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[ QUOTE ]
I know when MY CLUTCH fan kicks in man,,is it loud.


[/ QUOTE ]

Can you clarify this? My fan is running at idle when I first start the truck. When you say it "kicks in," do you mean it kicks into a higher gear and that is where the noise comes in?
 

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[ QUOTE ]
The fan-like noise can happen warm or cold but always when asking the truck to move. Never stationary. At first I considered the cooling fan on the engine- but that should not be kicking in when it is just started up and put into motion. It is also something I can’t quite see while rolling down the road.

[/ QUOTE ]

Working as designed. I'll explain in more detail below.

[ QUOTE ]
Sometimes, I can nearly complete a 30 mile trip and never hear the sound only to have it kick in as I start moving again at the stop sign down the street from my house. Occasionally, it seems a little hesitant to shift (only when fan sound is already present) and if I keep pushing down on the accelerator I get a terrible whine. The whine will go away as soon as I let up on the accelerator or the transmission up-shifts.

[/ QUOTE ]

Okay, here's the deal. The fan drive engages based on the temperature of the air coming out of the heat exchangers in front of the fan. At about 185F air temp (and look up a half-dozen recent posts from me about why this air temp is less than the coolant temp), the fan drive engages. Now, while you're running down the road, pulling your trailer (or not: on a hot day, with the AC on, mine will do this without the trailer), stuff is making heat, but there's air flowing through thanks to the vehicle speed. Now you come to a stoplight. Air basically stops. Air temp goes up -- there's still all that heat to deal with -- and the fan drive engages. But... it's not turning fast enough to be audible until the light changes and you accelerate away. You'll probably start to hear the fan somewhere above 1600-1800 engine RPM (I hear mine at about 1400-1500, but I'm also someone who is very well-tuned to this particular sound since it's key to what I do for a living).

And now you're up to speed again, air is moving through the exchangers, the air temp drops, and the fan drive disengages, lowering the fan speed enough that the noise goes away. Only to return at the next stoplight.

That part of it is entirely normal. It'll also do it after sitting overnight -- this is called "morning sickness" by fan drive engineers -- and will take a little bit for the drive to "pump out" when you first pull away in the morning.
 

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Discussion Starter · #5 ·
Thanks- all helpful so far. I might be able to sleep, not worrying about huge $$ for a new transmission right now.

The only thing i don't follow is how is the whine related to the fan?

I guess i could have discribed the whine better but well, isn't that all subjective?

I once had a bearing spin on on a 48" belt sander- the whine on the truck is very metallic and reminds me of the belt sander incident but not quite.

the first time i heard the whine you can imagine what was going through my mind! It is happening about 1-2 times a month now. but i cannot make it occur on demand- just that when it does happen it goes away as soon as i let off the throttle or the tranmission up shifts.
 

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Okay, you've got a 23.25" diameter, 9-blade fan, with about a 3" pitch to the blades. Spin it up over 1800 or so RPM. Guess what? It's gonna make a lot of noise as it moves all that air!

It sounds like a whooooOOOOOOOOOOOOOO as it engages. It's not subtle. And it's entirely normal.
 

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Drone is something else unrelated to cooling, not my area of specialty. /ubbthreads/images/graemlins/smile.gif
 

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Discussion Starter · #9 ·
I can totally understand the FAN noise; NOT the whine that sounds like metal on metal grinding- rubbing- sliding. It last happened 2 days ago when I had a bed load of gravel (~3000 lbs) sounded a lot like metal on metal or maybe a buzzer. But it was definitely coming from under the truck. My poor truck was making a horrible noise and it would not go away as I was attempting to climb a hill (about 7% grade).

I took the truck to the dealer and had the engine oil changed along with a transmission filter change and a complete transmission flush. Cost me a God awful $284.00, but immediately after the service I went and got another load of gravel and went up the same hill. No noise except fan- a huge relief. It was also a record breaking high temp for Colorado Springs.

I still have the old tranny filter so I could look at it. It is totally clean. The dealer said the fluid was as well- still looked new. The dealer topped off my coolant as well during the service inspection. Even without debris in the filter the sound not reappearing under the same conditions and my only change to the “system” being transmission fluid- it leads me to believe that my tranny is on its way out. Eventually, I believe the sound is going to return. Maybe a few thousand miles down the road as the fluid get “broken in”. – any thoughts?

On a complete inspection the only thing the dealer said they would recommend was possibly new shocks because they do not know how old they are- I took that as a "sell up". My truck is in immaculate shape even with the high mileage because I am overly anal on its maintenance- you know pay a little now or a lot later.
 

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Okay, let's make sure I have this straight:

You overloaded the truck. It made a scraping sound. You took it in and had fluids serviced, then overloaded it again and it did not make a scraping sound this time. That about right?

My guess here is that you compressed the rear suspension onto the overload springs -- and then some, and your metal-to-metal scraping sound was from the spring packs. Or the slip spline on the propshaft bottoming out by the carrier bearing. Or both.
 

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Discussion Starter · #11 ·
No I think you misunderstood what I said.

The truck makes the noise UNLOADED as well- randomly- only when FAN is already running. As for a description of the sound my fiancé agrees that is sounds like a buzzer going off underneath the truck. This particular instance the noise would not go away on the hill- maybe totally stopping it would have. Usually a change the gear will make it quit. The noise USUALLY only lasts 2-3 seconds. Following a complete flush = no more noise even under same load conditions. Dealer did a thorough checkout of truck - no damage to undercarriage or driveshaft. The noise still has not been back.

The 2002 F-350 is a class 3 truck with 10,000 - 14,000 GVW -I’ll check my empty weight ticket but I am pretty sure it was ~7500 empty and right off the handy-dandy label on the inside of the door jamb this particular truck had a 11500 GVW from the factory. I had tons of capacity left it had not even settled onto the helper springs. I'll take a picture on the next trip with a bed load of gravel. Since there is quite a lot of that to haul it shouldn’t be too far down the road until I have a picture for you- sometime after payday.

As I said I have 185,000 miles on this truck and most all of it has been under what I would term ‘significant’ loading. I am very anal about the maintenance and it care- I certainly never would have loaded this truck beyond its capacity and still got THAT kind of life out of it. How many people out there do not ever get a significant fraction of that kind of mileage without the loading? I know the Air Force F-350s don’t get much over 45,000 before they quit.

FYI: Most people believe the GVW can never be increased. For-the-most part that might be true. However, check out an ambulance mod for this truck. GVW goes up pretty substantially.
 

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May have just been a heat shield or something (skid plate?) loose and rattling in resonance, and in the process of dropping the pan on the trans, it got retightened, then.
 

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[ QUOTE ]
JIM: Thanks for responding..Did my post sound like WOOOooooooooooos to you?? Then a "SHIFT" to DROOOooooooon/ubbthreads/images/graemlins/vulnerable.gif /ubbthreads/images/graemlins/shrug.gif

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2012,
for goodness sake, man, stop beating yourself up so badly over all this. The WOOOOoooooos to the DROOOOOOOoooon that you describe is EXACTLY what my fan sounds like when it turns on. Every time. It takes as much a 15 seconds for it to fully engage at higher RPMS, so the sound changes, resulting in the "shift" sound you hear (sounds kinda like a torque converter lockup, right? That is because it is very similar in operation to a TC lockup). You are fine. You didn't hurt anything. Don't worry about it. It is normal. Drive your truck and be happy, I hate to see you get so tore up about this!
 
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