digits

Hi all,

my 2006 f150 with automatic gear box is making a very loud whining noise at high speeds (above 45 mph and higher speed = higher noise generally). If I release the throttle the noise disappears after 5 seconds, when I push the throttle again, the noise immediately reappears. I can not replicate the problem while stationairy (high rpm in neutral doesn't make a noise).

So my thoughts are, that these are not the causes:
- tirers (only when throttle pushed in)
- pulleys (only when actually moving)
- engine (nothing when stationary)
- airflow over cabin (noise disappears when throttle is released, at constant speed)

I have no idea where to look next or what to check next...

Thank you very much for any other hints! I check other topics, but they were always slightly different than what I am experiencing.

Kind regards,
digits

HeathMc

Possibly the rear end?

digits

What in the rear end would be affected by pushing the throttle? I thought it is mainly gears and bearings in the end, which would be moving/spinning all the time, even if you are coasting. But the noise is only there when the throttle is used.

EBC-150

Actually, that's exactly how most rear end noise 'operates'. To simplify it, it has to do with the torque being applied to the input of the bearings/gears with throttle. During a coast, the torque is applied 'backwards' on the same components by the wheels.

digits

Oh, interesting, good to know, I'll inspect the rear end more in detail!

HeathMc

If it is the rear end is whining it's probably gonna have to be rebuilt. Most of the time when the whining starts the damage is done.

effects4

My rear end was whining pretty bad. I expected the input bearing but it ended up being the differential bearing races, they had major pitting in them. Bought a kit off amazon and swapped in all new bearings and races in the garage in a couple of hours.

I have read a few cases where the nut on the pinion gear has come loose. Give the driveshaft a wiggle and see if it's that.

Check trans fluid level?