D0lphan72

I have a 2004 f150 xlt 4.6 RWD that whines upon acceleration or pushing on the gas pedal. It starts at about 40 mph and seems to get louder-ish the faster it goes. I hear it at about 80 mph too. By what I saw it shouldn't be the bearings because the sound goes aaay above 60 mph. The sound sounds like it's coming from the rear end but I'm not 100% sure. It goes away when the truck coasts but comes when you push on the pedal at all no matter what speed above 40 mph. I brought it to advance auto and had it scanned for issues and passed completely before this started. It drives perfectly fine and the tranny shifts gears just fine. The frame is virtually rust free as well. Any ideas? The noise is not very loud at all and none of my passengers notice it unless I ask them to listen to it. Is this a chance it's a non issue and just age? Thanks

Brutus442

I know you mentioned it seems to come from the rear but have a second person double check the idlers or tensioner while you rev the engine. Just to eliminate that as the possible source.

techrep

iTrader: (1)

After you have eliminated the idlers as mentioned above, I would look at the pilot bearing on the rear end.. has the rear diff ever been serviced ?

D0lphan72

Okay thanks guy! And idk about tre service history as I have owned it for a month. I asked the previous ow er if they have serviced the differential and am waiting on a response now. I'll try to find out and see where it's coming from. Do you think this is something I could ignore if the noise doesn't get louder in time?

techrep

iTrader: (1)

If it were my truck.. I would not ignore any noise. Normally things tend to get worse not better. I would suggest you get a service history from the PO if you can.

D0lphan72

still waiting on a response from the PO and I'm bringing it to a local mechanic for diagnostics on Wednesday. When either responds I will respond myself

RB06SCREW

Alternator is probably the culprit is it only when it's cold?

D0lphan72

I drove it the other day in 80 degree weather and it happened then too

digitaltrucker

Power steering?

D0lphan72

Idk why it would be power steering since it doesn't happen when I turn and it only happens when I accelerate at 40 mph or faster