[barrelsnpcs]

OK, I'm just a dumb ole girl and I don't know much about trucks. /ubbthreads/images/graemlins/shrug.gif I bought a 2002 Ford F250 Powerstroke a few months ago and just started pulling a 3 horse trailer. SOMETIMES, when I am pulling a loaded trailer up a steady incline, in Drive, not Overdrive, my truck makes this weird sound, like it's downshifting but it's not. The RPMs don't changing and it doesn't loose/gain power. It happens at around 2400-2500 RPMs.It's a startling sound. Someone said it might be the turbo kicking in??? It's kind of like a surging sound but the truck doesn't surge. I know I am making no sense. Any advice?
I put it in the shop thinking it was my transmission and they couldn't find anything wrong. Only happens when pulling a load. Is this normal??

 

[MrPlowJr_EZ_V]

Welcome to TDS!!!

Sounds like to me, you are getting what is called Turbo surge, or turbo stall, this occurs in the RPM range you describe, it is caused by air rushing back through the turbo. There are aftermarket housings you can get for the turbo that will help.

ATS is one of the suppliers.

Is the sound a sort of fluttering noise? or a screatching sound almost like letting air out of a baloon with the end stretched.

This sound is much more noticable under load, and also if you have an aftermarket intake setup it is nearly very noticeable.

Do you have a Chip or any aftermarket equipment? If you get a chance you might put some information in your signature letting us know what you've got.

 

[Bushwakd]

If you are in a hard pull and the truck heats up and reaches a hotter than normal temperature your fan clutch will kick on and run for about a minute to a minute and a half,which helps to pull more air through the radiater fins to help cool your anti-freeze to a safer temperature and then it will shut off until the temperature goes up again and it will cycle on and off again.It is controlled by a thermostat and when it kicks on it will sound like a jet airplane is under your hood.Also put as you mentioned a downshift with no change in pulling or speed change.

 

[barrelsnpcs]

Thanks for the "Welcome". Are you saying that this sound is normal and the housing will help muffle the sound? Or will the housing stop it from doing this? I don't have a chip or other aftermarket things on it except running boards. It's a 2002 Ford F250 2WD 4D with Auto transmission.

 

[Bushwakd]

If the sound appears when in a hard pull and then goes away shortly thereafter it is probably your Fan Clutch cylcling on and off.

 

[MrPlowJr_EZ_V]

If this infact is the problem, and sound you're hearing, then it will prevent the sound not by muffeling it, but it is a ported housing which will releive pressure imbalance.

Honestly without any aftermarket equipment, I think this sound would be barely noticeable.

These housings can be a little pricey if you're not 100% sure that is the sound, I would hold off, and perhaps get a second opinion.

 

[MOUNTAINMAN444]

If it sounds like it downshifts but the RPMs do not change, the first thing I would think is the fan clutch. When it kicks in it is loud (sounds like a downshift or a small jet under your hood) and if you aren't ready for it you will almost jump out of your seat (at least I do because I don't here it that often). This may not be what it is but getting used to this normal sound (fan clutch kicking in) is a whole lot cheaper than changing out the turbo housing.
Joe
P.S Welcome to the site and keep us posted on what you find out. I hate never hearing the end of the story.

 

[HoneyShucks]

"SOMETIMES, when I am pulling a loaded trailer up a steady incline, in Drive, not Overdrive, my truck makes this weird sound, like it's downshifting but it's not. The RPMs don't changing and it doesn't loose/gain power. It happens at around 2400-2500 RPMs.It's a startling sound."

No question about it. Normal operation of the fan clutch locking on to cool her down. Sounds like a jet headed up your exhaust /ubbthreads/images/graemlins/eek.gif

 

[barrelsnpcs]

I think a couple of you hit the nail on the head! I think it is the fan clutch. Yes, I do about jump out of my skin! Then, my knees started rattling because I was alone, pulling 3 horses, 150 miles from home, thinking my transmission was going! And it does sound like a jet under my hood or a downshift. And it's always at the top of a steady incline. Only last for a few seconds, too. THANKS so much for the information. I feel better and I can hit the road again without being paranoid! Other than this, this truck so far is a pulling machine! THANKS SO MUCH for the peace of mind.

 

[Casey_1]

[ QUOTE ]
in Drive, not Overdrive,

[/ QUOTE ]
Why not in overdrive? These trucks are designed to tow in overdrive. If the transmission isn't shifting frequently you can tow in overdrive and save fuel.

 

[JakeSpoon]

LOL
good job barrelsnpcs.

I too have always wondered what that sound was, just never asked anybody. I figured it was something like that...but never asked.

 

[Dozer Don]

Dittos
JakeSpoon

I was thinking the same thing...

 

[mitley_350]

Once the sound starts, how long does it stay on? Should stay on for a about a minute. If the sound is coming and going every second or so, then this is a known problem.
Had my 2002 fixed about two years ago for the rapid cycling. Now it comes on and stays on for around a minute.

Tim

 

[JakeSpoon]

yeah, mine only does it for a minute or less.
And, only on long hauls,(never notice it in town)
usually when im stopping or at a dead stop.

 

[avi]

[ QUOTE ]
[ QUOTE ]
in Drive, not Overdrive,

[/ QUOTE ]
Why not in overdrive? These trucks are designed to tow in overdrive. If the transmission isn't shifting frequently you can tow in overdrive and save fuel.

[/ QUOTE ]Because she is climbing a hill and her RPM's are in the 2400-2500 range which is great for climbing. It sounds like she is taking it out of overdrive and driving the truck perfectly /ubbthreads/images/graemlins/smile.gif

 

[jd730d]

Read this:

2002/03 F-Series and Excursion Belt Squeal; 99-01 with Replaced Belts:
Some 7.3 engines may exhibit a loud squeal noise from the engine area when the engine is under load and the fan clutch is locked up, typically in hot and dusty conditions. Another complaint may be the fan clutch oscillating or not locking up. This may be due to dust accumulating on the back side of the belt and causing it to slip on the water pump pulley. This usually affects only 2002 model/year vehicles, but may occur in trucks built from 99-01 if the belt was replaced after July 01. On single rear wheel trucks, replace the serpentine belt with P/N 1C2Z-8620-NA on single-alternator engines, and 1C2Z-8620-PA on dual-alternators. Broadcast Message 3848.
A service kit has been released for 2002 trucks only. It includes a belt, tensioner and water pump pulley. Use 2C3Z-8620-AA for single alternator and 2C3Z-8620-BA for dual alternators. Broadcast Message 0718.

 

[IA712]

jd730d - That is exactly my problem, do I get the parts from the stealer or can I get them from NAPA? /ubbthreads/images/graemlins/shrug.gif Also, if I am going to have to change the belt, it would probably be a good time to flush my tranny and go from the green to the gold. /ubbthreads/images/graemlins/grin.gif Changing the top radiator hose at the same time, to the hose that is made for the dual alternator truck, that way one will not have to remove the hose next time you want to replace the belt.

 

[T_Bone]

Hi barrelsnpcs,

There's not a thing wrong with your truck. At 2500rpm the fan will automaticly come on. To prove this is what your hearing, drop your rpm's too 2250rpm or so and you will here the fan kick off. Increase rpm to 2500rpm and the fan will kick back on.

I don't normally use turbo rpm for pulling my loads (16kGCW), about 1600rpm to 1750rpm (best fuel mileage), but last week I was pulling heavy (31kGCW) so I had to use some turbo power, 2250rpm to 2500rpm, I too thought the fan was noisy. To prove that this indeed was fan noise, on a flat road I kick'd it up to 2500rpm and the fan came on. So the fan will come on at 2500rpm without the need for extra cooling, like it does for pulling grades.



/ubbthreads/images/graemlins/smokin.gif

 

[MrPlowJr_EZ_V]

[ QUOTE ]
jd730d - it would probably be a good time to flush my tranny and go from the green to the gold. /ubbthreads/images/graemlins/grin.gif

[/ QUOTE ]

I would recommend sticking with the Red Mercon on in the Tranny, the radiator/cooling system might not have such a fit over the differecne in fluids. /ubbthreads/images/graemlins/biggrin.gif


Sorry couldn't resist. /ubbthreads/images/graemlins/cool.gif

 

[IA712]

Thanks for pointing that out.... /ubbthreads/images/graemlins/blush.gif
I meant flushing my radiator... /ubbthreads/images/graemlins/ooo.gif