Hello All,

This is my first post on this forum (as I just bought my truck today).

I purchased a 2004 F250 SD/Crew/Lariat 4x4 8cyl Turbo Diesel. The vehicle has 137k miles. I purchased this truck to haul a horse trailer and for general farm needs.

In any event, during the test drive.... everything was (relatively) smooth so I pulled the trigger and bought the truck. Fast forward 5 hours (until I had a second driver to go over and pick up the truck with me).... I get out onto a local highway while headed home and start to hear a "whine/groan" coming from what i believe is the "rear end".

It starts almost as soon as I get the truck rolling with a low groan/wine which eventually gets louder (which is when i heard it) when i hit highway speeds. It sounds like an old "police" or "air raid" siren.

While moving, I shifted into neutral to see if it was a noise in the driveline while under load.... no change. The noise/whine gets louder and softer as vehicle speed increases or decreases.

Its not related to RPM... the truck has tons of power and doesnt miss a beat...no smoke from the exhaust either.

So im left with a noise that is rotational, gets louder and softer as vehicle speed increases or decreases. The noise is a moan/groan like a siren, it is independent of the vehicle being in drive and seems to localize in the rear.

Im left thinking rear wheel/axel bearing vs differential/pinion bearing noise. What are your thoughts?

Im honestly a bit irked as the truck did not come with a warranty and it did not make these noises earlier this morning when I initially test drove the truck. I realize its a 12 yr old vehicle, so im not really complaining, I just want to fix it so I can get back to enjoying my purchase and getting some work done.


Many Thanks for your time and input.
M.L.

 

drain and refill the rear gearbox with the correct fluid