Whistling noise
02-24-2011, 09:05 AM
#24
My truck is an automatic and I think the whistling noise comes from the transmission vent. The vent is designed to release pressure that builds in the transmission, and usually becomes coated with a little transmission fluid. The vent is covered by a cap to prevent reverse flow of air. Air pressure from inside the transmission will lift the cap to vent the air. During cold weather the oil-coated cap won't always move freely and may only partially lift or get cocked, causing the escaping air to whistle.
The noise stops or changes pitch when you let off the throttle because the pressure inside the transmission is reduced, and unless the vent is badly oil-soaked and dirty, the whistling only occurs during cold weather when the oil is coagulated from the low temperatures. In my truck, the whistling noise is worse when the truck is cold and will usually lessen as the transmission warms, but not always. I'm at 95K miles and my vent probably needs to be cleaned, because on some days it won't whistle at all and I think it's due to the cap being stuck at full open. Remove the vent/cap assembly and either clean or replace it...you may also want to change your transmission fluid. Dirty and/or well used fluid will more easily "gum-up" the vent.
The noise stops or changes pitch when you let off the throttle because the pressure inside the transmission is reduced, and unless the vent is badly oil-soaked and dirty, the whistling only occurs during cold weather when the oil is coagulated from the low temperatures. In my truck, the whistling noise is worse when the truck is cold and will usually lessen as the transmission warms, but not always. I'm at 95K miles and my vent probably needs to be cleaned, because on some days it won't whistle at all and I think it's due to the cap being stuck at full open. Remove the vent/cap assembly and either clean or replace it...you may also want to change your transmission fluid. Dirty and/or well used fluid will more easily "gum-up" the vent.
Does anyone know where this vent is located???
03-11-2011, 10:49 AM
#26
F150 2005 V* Owner
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Same problem solved
I have a V8 4.6 in my 2005 F150 XLT and had the same problem in cold weather. After i was told that this was a "normal" noise, I had it checked and finally, they changed the alternator, the binder and a pulley but the main problem was the alternator.
03-15-2011, 10:09 PM
#29
I have had the same problem for four winters now and it is definatley not the alternater. Its a whistle, not a squeal. It only happens sometimes in cold weather. It did happen this morning but after driving a few blocks it stopped. Tried having the dealer look at it under warranty but of course...no whistle that day! I would love an answer to this.
03-15-2011, 10:48 PM
#30
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Same problem. first year with this truck only noticed it when it got colder.
06' XLT 4.6L.
Sounds like the 5.4 and the 4.6 are having the same issue. I'm not a mechanic. Do they have the same intake design? Do they both have this vent on the tranny? Maybe we can narrow it down that way.
06' XLT 4.6L.
Sounds like the 5.4 and the 4.6 are having the same issue. I'm not a mechanic. Do they have the same intake design? Do they both have this vent on the tranny? Maybe we can narrow it down that way.
