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I notice a high pitched sound during acceleration to maintain speed, stops immediately when I take my foot off the gas pedal. I’ve got an ’04 F150, 2 WD w/ tow package. The truck has always made this sound. It’s not excessively loud, you really have to listen in order to hear it.
I’m assuming it’s the limited slip rear axle differential and (hoping) that it’s normal. Or do I need to have it examined?
I’ve never heard what a worn out differential sounds like, but what I’m hearing is about what I’d imagine it would sound like. Although it’s not very loud, I noticed it right after I bought the truck new. It’s been two years and 20,000, hasn’t got any louder, but it’s there so I guess I’d better have it checked out.
Bring it in under warranty. It could be the ring and pinion. Ford had issues with the rear diffs mostly with the larger 9 3/4 limited slip units. Eventually it will get louder and it could get real expensive if its no longer under warranty.
Mine did the same. Take in for warranty as suggested. Some dealers do kit. Mine was the whole rear end replacement. Cheaper than the labor for the Kit.
Mine did the same thing, I still cannot pin it down. It happens uphill while accelerating, as soon as I let off the gas it stops. I cannot tell if it's the rear end, tranny or motor. My wife hangs her head out the window to listen but shes not very good at identifying where the noise is from, it's sorta like a whistle coming from the right side and I can't remember if it's in a certain gear or not. I've taken it to the dealer but there are no hills in the dealer parking lot to test it.
I notice mine more while cruising at speed, on level ground 60-70 mph. I'm thinking differential because it's only during acceleration. The Michelins on my truck actually make twice as much noise as the whine I'm hearing. You have to listen very closely, then it's like you said "as soon as I let off the gas it stops", tap the acccelerator and I hear it again. I'm goiong to take it to Ford, hopefully they'll make an accurate analysis. I also have rear brake rotor issues, rotors are grooving excessively on the outer surface only, inner surface is smooth.
had the same problem and the dealer warrantied it. it is all fixed. let me pull out my service invoice and i will tell you exactly what they did. both the wining at highway speed that went away when i got off the gas, and the rear end chatter around a corner