# Rear Differential or Wheel Bearing? **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [February 6, 2008, 11:21pm UTC](https://community.cartalk.com/t/rear-differential-or-wheel-bearing/10310 "2008-02-06T23:21:53Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![lcmatrix](https://avatars.discourse-cdn.com/v4/letter/l/e99b99/32.png) [@lcmatrix](https://community.cartalk.com/u/lcmatrix)\ **Post date:** [February 6, 2008, 11:21pm UTC](https://community.cartalk.com/t/rear-differential-or-wheel-bearing/10310/1 "2008-02-06T23:21:53Z")
My Toyota Matrix (AWD/automatic) makes a “whirring” noise that comes from the rear of the car. It gets more high pitched at increased speeds. I’ve received 2 mechanic’s opinions: 1) It’s the rear differential 2) It’s a wheel bearing. Is there a way for me to tell who’s right or should I go for a third opinion? ---
**Author:** ![Docnick](https://avatars.discourse-cdn.com/v4/letter/d/ecae2f/32.png) [@Docnick](https://community.cartalk.com/u/Docnick)\ **Post date:** [February 6, 2008, 11:56pm UTC](https://community.cartalk.com/t/rear-differential-or-wheel-bearing/10310/2 "2008-02-06T23:56:47Z")
Is this a 4 wheel drive Matrix? If so, it could be either a wheel bearing, differential or somthing dragging on the rear brakes. Since neither mechanic knows enough to diagnose the problem, I would seek a knowlegeable third opinion, and have that mechanice drive the car first. I had what I thought was a rear wheel bearing problem on a rear drive vehicle and it turned out to be the Positraction differential bearings. A $450 problem. ---
**Author:** ![pleasedodgevan](https://avatars.discourse-cdn.com/v4/letter/p/51bf81/32.png) [@pleasedodgevan](https://community.cartalk.com/u/pleasedodgevan)\ **Post date:** [February 7, 2008, 5:22am UTC](https://community.cartalk.com/t/rear-differential-or-wheel-bearing/10310/3 "2008-02-07T05:22:55Z")
That there problem could also be a u-joint but usually a driveshaft is much older when it starts to do that.