Differential noise always sounds like a hydraulic pump

2002 FORD F-150
184,000 MILES • 5.4L • V8 • 4WD • AUTOMATIC
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RABIDESKIMO360
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Always sounds like a hydraulic pump. Even at 1 mph gets louder and faster with speed. Sounds like a garbage truck picking up a can. Purchased used from a dealer. Rear end had a leak. Replaced gasket and fluid new. The internal components look brand new nice shiny silver/grey metal on all parts other than housing. Wondering if maybe they didn't shim it properly or maybe a bearing when they rebuilt it?
Feb 24, 2020 at 7:59 PM
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JACOBANDNICKOLAS
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Hi,

It could be need shimmed, the ring and pinion may not have been properly set up, and it could be a bearing. Usually, a bearing will chance pitch when turning. Does that happen?

Also, is it loud enough to record on your phone and upload it for me to hear?

Let me know.
Joe
May 17, 2021 at 1:25 PM
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RABIDESKIMO360
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It only changes pitch when I accelerate and decelerate, I ordered a master rebuild kit with all of the bearing shims and such and axle bearing since I'm gonna be in there anyway and have them pulled out. The drive-line is tight no play in rotation or front to back. In fact it almost seams too tight if that's even possible.
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May 17, 2021 at 1:25 PM
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JACOBANDNICKOLAS
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Wow! Yep, I hear it. It sounds like a bearing. It could also be the ring and pinion were not properly set up, the pinion nut was over tightened and so on. Do you know which differential it is? It can be any of the following.

Ford 10.25 Inch Rear Axle
9.75-Inch Ring Gear
Ford 8.8 Inch Ring Gear

Let me know and I can get you the specs and procedures.

I listened to it again, and to me it sounds like a bearing. I have a feeling (can't be 100% sure) but it sounds like it's the pinion bearing. If it wasn't torqued properly, it can be damaged.

Let me know.
Joe
May 17, 2021 at 1:25 PM
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RABIDESKIMO360
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It's the 9.75. I already ordered the master rebuild kit with all of the bearings and the nuts and bolts and shims and the yellow marking grease and everything was $250.00. I also got both axle bearing since I'm going to have the shafts out anyway I figured I'd just do the whole thing from scratch. Thanks for confirming my assumption.
May 17, 2021 at 1:25 PM
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BMDOUBLE
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Yes that sounds like a bearing for sure!
May 17, 2021 at 1:25 PM