I've been hearing a rattle on and off for awhile now. mostly around 30-45mph. I put it in nuetral and it doesnt go away, remains constant. almost sounds like a bad throw out bearing type noise.. today I was on an onramp and happened to have the window down with a wall on one side so I could really hear it.. lasted 20-30 seconds and then there was a small thump or thud and all was quiet again. almost like something engaged..?? tranny? transfer case? no idea wut it is.. a few months ago I heard the same rattling noise going about 35 n then it just dissapeared.
62,000
5.4
4x4
auto
6" fabtech

 

almost sounds like this (link below) but not quite the same. also I'm always on flat roads going mosatly straight. except one time it started going down hill. but it comes and goes imediatly, like someone throws a switch. and today was the first time there was a thump right as it stopped. I guess I'll check out the vac lines to the hubs to start.
if it was the 4x4 engaging on one side wouldn't you feel something in the steering wheel??


https://www.f150online.com/forums/20...-bearings.html

 

or this
https://www.f150online.com/forums/20...rd-rattle.html

but im not really under load.. just holding constant speed. I can pin it from dead stop to100 and it doesnt do it.. or up a big hill I travel everyday and it doesnt seem to do it.

 

so I went up in the snow this past weekend.. in 4x4 from a stop it makes loud 'pop' sound. kinda a ting. reverse, drive. every time I start out. doesn't sound too good...

so i heard the normal noise, 2x4 going about 30 n rain. I put it in 4x4 while maintaining speed and noise disappears

I did this 2 days in a row. so like the other posts, when I put it in 4x4 the noise is gone.

 

 

I blame the bald tires..

 

yes yes. use the search..

https://www.f150online.com/forums/20...replacing.html