[guardrail22]

On I26 on Friday pulling new 9000# travel trailer, we crossed into NC and started up Saluda Grade with cruise control set to about 65mph.

As we move up the mountain, truck shifted down to 4th, boost approached 30psi and EGT was near 1200F – all to be expected. Suddenly the truck shifted down to 3rd, I started to hear a high pitched whine in addition to usual noises, the boost needle went to like 50psi (off scale), cruise shut off and then everything was fine.

I’m betting that the speed set in the cruise was too high for 3rd gear and it hit the rev limiter about the time the compressor surged but everything has been fine since. I did hear the noise twice, once on decel and once from standing start turning a corner but the cruise is fine and everything seems ok.

Anyone ever had this happen?

 

[jgoff78]

yes i have, the most boost i have ever seen on my truck is 27 with the extreme tune. i was towing about 9k too and was getting on the freeway from an on ramp. when i gave it a little extra power it downshifted into 3rd at about 58-60 my boost only hit 41 on my digi gauge and then stayed at 35 till i backed it down. i didnt know what it was till i looked at the gauge and saw 41. loud whine like you said then its never done it again. my service manager has seen my truck do some other stuff where it wont spool boost and different things but cant get it to do it himself. i told him i think i need a new turbo when i told him this he agrees. hes going to a meeting with the navistar engineers and his purpose there is for my turbo alone. ill let you know how it turns out.

 

[Clevelandjim]

[ QUOTE ]
I started to hear a high pitched whine in addition to usual noises

[/ QUOTE ]

Possibly the cooling fan? It sounds like a jet engine.

 

[Old_Dog]

The TorqShift's 3rd gear ratio is 1.54:1. When you were doing 65-mph in
OD the engine shoulda been spinning about 1,879-rpm with a 3.73:1 rear-end
and stock tires (655 revs/mile). When your tranny downshifted to 4th gear
you'd be doing 2,647-rpm at 65-mph. Then the downshift to 3rd gear
would jump the engine to 4,076-rpm, if it were not rev limited. You
can imagine the exhaust flow into the turbo during that downshift into
3rd gear while the PCM figures out its in an over-rev situation and
cuts the cruise control...

That jump from 4th gear's 1:1 ratio to 3rd gear's 1.54:1 ratio is too
big. With a 6-speed stick you coulda kept cruising at 65-mph in 3rd
gear with its 1.3:1 ratio, spinning the engine at 3,441-rpm, which is
just slightly above where the horse power peak occurs at about 3,300-rpm.
And no torque converter slippage!

What's the rev limit on the 6.0-L? Looking at the 6.0's torque and HP
graphs, its in a steep nose dive starting around 3,600-rpm... So
probably rev-limited around 3,800-rpm to 4,000-rpm.

--Old_Dog

 

[guardrail22]

in 55000 miles I'd have expected the radiator fan to have come on before now. I've never heard anything this loud or this pitch before.

 

[F350Lariat]

I have never had this one happen before ... then again I would never have cruise set on a 7% grade pulling a 9000# load. You never know what will happen when the truck is on auto pilot under that type of stress.

I suspect the RPM limiter was hit. It occurs around 4000 RPM. Someone will chime in with the exact figure. The whining is most likely a turbo or engine fan.

 

[lincster]

I hear the high pitched squeal everytime I come down a grade pulling my trailer and the tranny downshifts to help with braking. I can hear the fan on at the same moment and then it down shifts and squeals. Lasts a second or so and then stops. I don't worry about it, just keep on rolling......

I also never tow with the cruise on. Cruise makes the computer do whatever to maintain speed, not a good idea in my book.

 

[ikidd49]

Just a thought for you. If you have had a later computer flash you will probably find (as I did) that the cooling fan comes on much more frequently ...my suspicion is that the parameters for its operation have been changed significantly....I had never heard mine come on in the first year of operation (towing mostly) however as soon as I had the reflash last August I often hear it when it is working hard towing. Even had it come on while climbing a hill into the centre of Big Bend Park resort area on a cool day this February and it was unloaded with just 2 of us and the hitch! It does sound like a a jet!!! /ubbthreads/images/graemlins/eek.gif /ubbthreads/images/graemlins/eek.gif
BTW mine will rev up to about 4000 on a steep downhill when in TH. I've never pushed it that hard up a hill with the trailer so can't speak to that. I find that towing in the hills/mountains the cruise is more of an irritant than a help.
Ian

 

[CalConInc]

I blue a turbo once and you get a squeel before it goes, but it also sounds like metalic clunking.

However, the pressure can really build up and escape through the hoses at the clamps if the need tightening.

If you got sooty greese blowing outon the turbo around the hose clamps, you may be able to tighten them. It may be that's all it is. I had that happen on another psd.

Pat

 

[Machine]

[ QUOTE ]
Just a thought for you. If you have had a later computer flash you will probably find (as I did) that the cooling fan comes on much more frequently ...my suspicion is that the parameters for its operation have been changed significantly....I had never heard mine come on in the first year of operation (towing mostly) however as soon as I had the reflash last August I often hear it when it is working hard towing. Even had it come on while climbing a hill into the centre of Big Bend Park resort area on a cool day this February and it was unloaded with just 2 of us and the hitch! It does sound like a a jet!!! /ubbthreads/images/graemlins/eek.gif /ubbthreads/images/graemlins/eek.gif


[/ QUOTE ]

My fan came on yesterday for about 5 seconds after accelerating from a red light; unloaded, with the outside temp being 101*.

 

[zmc501]

Unless the terrain is really flat and I can keep a constant speed, I never use cruise while towing.

 

[mackey]

Ford's spec calls for 22-24 psi. I was seeing 30 psi on hard pulls till turbo quit with 9000 miles. New turbo only shows 24 psi on same climbs.

Bill

 

[TaylorMax]

I drive truck for a living and you never ever run the cruise control when mountain driving. With that said, the cruise control is going to try everything to keep the speed @ 65mph but the PCM will shut the cruise down to prevent damage happening to the engine because of the rev limiter.


There is nothing more exciting than hauling 80,000# going down a 5 mile 8% grade in the snow and a dumba$$ in front of you. Kinda gets your heart pumping and your knuckles white.

 

[guardrail22]

interesting comment about cruise.

with the old trailer it would handle it easy but it was only 4500#.

will be going over hill and dale to Devils Fork Friday and will experiement a bit.

Coming back from New Hampshire it pulled fine in many areas but there was nothing like Saluda on that route.

is the fan controlled by the computer or just a thermostaic clutch? I'd like to dummy it and see what it sounds like.

 

[guardrail22]

do you notice a loss of performance with only 24psi of manifold pressure?

 

[tincan]

[ QUOTE ]
Unless the terrain is really flat and I can keep a constant speed, I never use cruise while towing.

[/ QUOTE ]
Ditto /ubbthreads/images/graemlins/biggrin.gif

 

[hiall]

[ QUOTE ]
As we move up the mountain, truck shifted down to 4th, boost approached 30psi and EGT was near 1200F – all to be expected. Suddenly the truck shifted down to 3rd, I started to hear a high pitched whine in addition to usual noises, the boost needle went to like 50psi (off scale), cruise shut off and then everything was fine.


[/ QUOTE ]

The squeal was probably the turbo thrust bearing as the load on it at 50 lbs of boost is quite high. The oil gets pushed out of the bearing and the metallic squealing sound is the turboshaft running dry on the bushing/bearing.

EB sensor prolly toast making your vanes close up and overboost at WOT.

Been in for the recall yet?

 

[guardrail22]

everything is running fine, in fact I towed the trailer 60 miles to Devils Fork last Friday. In fact the cruise worked while towing.

Been in for recall? I have more software versions than Microsoft Windows !!!!

Last one was the one that told the computer to ignore a sensor.

I think my next sevice is 62500 miles. I'll have to have them check over some things in the intake system while its in then.

 

[JDeere5105]

Hey guardrail the Saluda grade can be ugly. I live off of the exit at the bottom of the grade (Columbus/Tryon). Jackson's towing service, here in town, gets plenty of business from that thing /ubbthreads/images/graemlins/smile.gif Where do you live in NW SC? I lived in Greenville for 25 years. Man is it still growing. (Still work there) Anyways good luck with the truck.

Jason

 

[guardrail22]

between Greenville and Greer near Riverside HS.

My Tech leader lives north of 26 off the Columbus exit