Strange noise from rear. WHAT IS IT?!?!

[Steve Robinson]

I have a 2011 Tahoe 4x4 and I have been hearing a strange noise from I think the rear. I have searched extensively on YouTube and internet for a matching issues to help me figure out what it might be but none Of what I’m finding sounds like the noise my truck is making.

The noise description as best as I can explain it: when going slow it is a thud sound that happens as the truck is moving but only in drive or reverse. Not in neutral. As I speed up so does the noise and at 70-80 it sounds like a whirring/whining sound.

When coasting it lightens up but when accelerating or slowing it gets louder (not crazy loud) but just enough to hear it clearly.

It is hard to tell exactly where it is coming from but it does seem to be louder towards the back when driving (had my girlfriend climb in the back to listen).

What do you guys think? Has anyone had this issue and figured it out before?

 

[wjburken]

I have a 2011 Tahoe 4x4 and I have been hearing a strange noise from I think the rear. I have searched extensively on YouTube and internet for a matching issues to help me figure out what it might be but none Of what I’m finding sounds like the noise my truck is making.

The noise description as best as I can explain it: when going slow it is a thud sound that happens as the truck is moving but only in drive or reverse. Not in neutral. As I speed up so does the noise and at 70-80 it sounds like a whirring/whining sound.

When coasting it lightens up but when accelerating or slowing it gets louder (not crazy loud) but just enough to hear it clearly.

It is hard to tell exactly where it is coming from but it does seem to be louder towards the back when driving (had my girlfriend climb in the back to listen).

What do you guys think? Has anyone had this issue and figured it out before?

Welcome to the forum Steve.

Nice excuse to get the girlfriend into the back.

A couple questions:
How many miles on the vehicle?

Anyway you can post a video that captures the sound or is it more like you feel it vs hear it?

It could be a couple things. First off, if you don’t know when the rear differential fluid has been changed, or it has been over 50K miles, I would pull the cover, drain the fluid and see how sparkly the fluid is. If it looks like a glitter bomb went off, you probably have issues. If you have chunks of metal, you definitely have a problem.

Get underneath and check you u-joints. Shouldn’t be hardly any play when you grab the driveshaft and try and move it side to side or up and down. Also pay attention to the input to your rear differential.

It could also be an axle bearing. Does the sound change if you turn to the right vs the left vs straight? While your girlfriend was in the back, did it feel/sound like it was louder on one side or the other?

 

[OR VietVet]

I think it is related to the driveshaft or the rear diff or both. Especially since it is speed sensitive. How old is the rear diff fluid? Pull the fill plug and reach in and get a sample to see what the fluid looks like. You do not want to see grey or have any metal floating in the fluid. To get the best look you should remove the cover and check all the bearing and gear teeth. May have to remove the driveshaft and inspect u-joints. Check the axle seals and check for axle bearing.

Welcome to the forum.

 

[iamdub]

Difficult to go by the description, but my first thought is U-joint.

 

[Joseph Garcia]

Welcome to the Forum from NH.

It looks like you've already got great suggestions from folks here on what to check out first, in order to determine the source of your issue.