Hello, I have a 2004 F150 5.7L supercrew.Last week I had the pinion replaced in the rear because it had a loud hum while gas pedle was pressed. I thought the noise was gone, but now I hear a slightly softer hum from 45 to 55 mpr when I am just cruising along with the gas peddle slightly pressed down. Now, I called the dealer and they said that this was a normal noise or hum for similar F150s. Is this true or do I need to go back? I am 80 miles from end of factory warranty.

 

That is not normal mine is silent sounds like they don't have the ring and pinion set up right don't let it go off warranty.

 

They replaced the pinon AND ring gear, right? It seems crazy to not replace both if that was the suspected source of noise. Kind of like replacing a worn out chain on a motorcycle without replacing the sprockets too, the old will wreck the new eventually.

 

you are correct the pinon and ring gear, but I still hear a similar but softer humming sound. Mostly now from 45 to 55mph.
I did get Ford extended factory 35/35000 supreme or gold package so I should be good with taking it back in this week. And I will take it back in. Thanks.