i have a 03 f150 supercrew 4x4 with 33000 miles, and i've noticed that when i floor it and it winds out and changes into 3rd, there is a squeal that comes from the back end of the truck. any suggestions?!

 

Are you sure it is from the rear of the truck ?

Most of the time someone reports a squeal when the tranny shifts it is because their serpentine belt slips.

Get a Goodyear Gatorback belt and I bet your squeal goes away...

 

I agree it's probubly the belt.

Sounds have a way of traveling in a vehcle. I've replaced several rear outer axle bearings in different makes over the years. The sound almost always seems to be coming from the front.

Doug

 

I also experience this squeal when I floor my '01 and it shifts into third. I don't see how the transmission shifting causes the belt to slip.

 

Because the engine is dropping rpms quickly the belt slips for a second. Trust me it's the belt they all do it. Get a gatorback.
Alan

 

I suppose that does make sense that when the tranny shifts it looses RPMs for a second and all the compenents are still spinning faster than the crank shaft.