# Humming/Groaning in rear (center) under trunk

**URL:** <https://community.cartalk.com/t/humming-groaning-in-rear-center-under-trunk/188952>\
**Category:** Maintenance/Repairs\
**Tags:** charger, dodge\
**Created:** [February 3, 2023, 9:32pm UTC](https://community.cartalk.com/t/humming-groaning-in-rear-center-under-trunk/188952 "2023-02-03T21:32:40Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Brogan15](https://avatars.discourse-cdn.com/v4/letter/b/a587f6/32.png) [@Brogan15](https://community.cartalk.com/u/Brogan15)\
**Post date:** [February 3, 2023, 9:32pm UTC](https://community.cartalk.com/t/humming-groaning-in-rear-center-under-trunk/188952/1 "2023-02-03T21:32:40Z")

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started to hear the sound of a wheel bearing going bad in my rear passenger side tire so I changed out the wheel bearing. I still hear the same humming/groaning sound but the noise now seems to have moved to the center and is coming from under my trunk. the noise is audible when driving 20mph+ and only changes pitch with the speed of the car. I am thinking it may be the rear differential but was hoping someone else had some advice in case it could be something else. It isn’t tire noise or wheel bearing on the other side. idk what else it could be… Thanks!

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**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\
**Post date:** [February 3, 2023, 9:34pm UTC](https://community.cartalk.com/t/humming-groaning-in-rear-center-under-trunk/188952/2 "2023-02-03T21:34:56Z")

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When was the last time the rear diff fluid was serviced?

Tester

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**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\
**Post date:** [February 3, 2023, 9:42pm UTC](https://community.cartalk.com/t/humming-groaning-in-rear-center-under-trunk/188952/3 "2023-02-03T21:42:58Z")

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Sounds like a diff bearing to me.

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**Author:** ![weekend-warrior](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/weekend-warrior/32/26122_2.png) [@weekend-warrior](https://community.cartalk.com/u/weekend-warrior)\
**Post date:** [February 3, 2023, 9:46pm UTC](https://community.cartalk.com/t/humming-groaning-in-rear-center-under-trunk/188952/4 "2023-02-03T21:46:53Z")

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[Dodge Rear Differential Lawsuit Includes Challengers and Chargers | CarComplaints.com](https://www.carcomplaints.com/news/2021/dodge-rear-differential-lawsuit-challengers-chargers.shtml)

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**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\
**Post date:** [February 4, 2023, 12:08am UTC](https://community.cartalk.com/t/humming-groaning-in-rear-center-under-trunk/188952/5 "2023-02-04T00:08:34Z")

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Is your rear differential a limited-slip design? If so, could be the gear oil’s additive needs replacing. Not slippery enough, differential clutches sticking. Esp consider this possibility if noise becomes more apparent when turning (even sightly) at slow speed. I’ve had that problem on my truck, sort of sounds like the brakes are making noise. Replacing additive (mostly) fixed it.