This may be one of the stranger questions – I need a listening device – not my cell phone.

My 2007 5.7H 2WD 3.92 Rear-end Aspen with 110,000 miles has developed over the past few months a whine in the drive-train. I just changed out the differential oil [Valvoline full synthetic gear oil 75/140] and saw nothing that I could recognized as wrong (a couple pics attached). But I know not about drive trains.

The only clue I have (not much) is that the hum/whine, I hear, is at 35 to 45 MPH when cruising and decelerating – but when I shift it to neutral, the sound stops. So, no sound when no load. Am sure I don’t hear it at higher speeds because of engine/exhaust noise.
In my perfect world there exists a magnetic (or strappable) sound recording contraption I can attach to the differential or transmission to isolate the noise. Heard or seen of such a thing?

I am also skittish about taking it to a random shop and them telling me they need to start replacing things to see what fixes it. Any awesome drive train shops in Columbus Ohio, USA?






Thanks for any input you can provide!

 

The cheapest way would be to DIY something, but there are some ready solutions out there, like STEELMAN 06600

 

Only thing I can think of is to use a GoPro camera. While in it's case, you can tie-strap it in different places, start recording and go for a drive. This will give you audio and video.

 

Diffs are simple metal parts. When wear/play occur these shed small metal dust/flakes.
You can drain a diff and simply take a magnet and swirl around the old fluid ( yes it sticks to the covers etc) point being it'll attract these flakes. Failed parts will have alot. You're pics don't indicate heavy wear/damage.
Get it on a lift and locate the exact noise location and start there.

 

Thank you bradleybbb. I appreciate your insight. Though I own a shiny new Steelman 60635 to isolate the whine, I blew out a rotator cuff soon after I bought the Steelman and have yet to get back under the truck. Hopefully before the first snow. I suspect bearing(s) but which one(s), I have to find out.

 

Damn, I hope ya get better ASAP. Follow docs advice. I didn't and set me back min. 6 mo.
Wish ya the best....Peace