Towing hard, when the engine revs up, the fan clutch is acting strangely.
When the truck unlocks in 6th, or even kicks down to 5th:
1) very high pitched squeal (almost inaudible) and
2) the fan RPMs cycle up and down (1 sec at 3k, then 5 sec at 2.5k).
It is similar to this post:
http://www.thedieselgarage.com/forums/19-2003-2007-6-0l-power-stroke/116734-high-frequency-noise-under-load.html
However, I think it is more fan clutch/bearing/belt related than degass cap leaking. It is very repeatable with the engine RPMs and the fan clutch RPMs. As soon as the tranny locks in 6th again, the sounds immediately stop.
I've posted a video of the problem:
fan clutch wierdness
It's really hard to see and hear what's going on. Turn your volume up really loud. I'm pulling a hill that required me to downshift. As soon as the downshift happens, you can hear the high pitched squeal and then the fan speed cycle up and down.
The dominate sound is the fan speed cycling up and down, but the squeal is there, just so high pitched it might be inaudible to some of you grey beards.
Thanks for the advice!
When the truck unlocks in 6th, or even kicks down to 5th:
1) very high pitched squeal (almost inaudible) and
2) the fan RPMs cycle up and down (1 sec at 3k, then 5 sec at 2.5k).
It is similar to this post:
http://www.thedieselgarage.com/forums/19-2003-2007-6-0l-power-stroke/116734-high-frequency-noise-under-load.html
However, I think it is more fan clutch/bearing/belt related than degass cap leaking. It is very repeatable with the engine RPMs and the fan clutch RPMs. As soon as the tranny locks in 6th again, the sounds immediately stop.
I've posted a video of the problem:
fan clutch wierdness
It's really hard to see and hear what's going on. Turn your volume up really loud. I'm pulling a hill that required me to downshift. As soon as the downshift happens, you can hear the high pitched squeal and then the fan speed cycle up and down.
The dominate sound is the fan speed cycling up and down, but the squeal is there, just so high pitched it might be inaudible to some of you grey beards.
Thanks for the advice!