How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask GM-Frank Your Own Question
GM-Frank, ASE Master Certified
Category: Car
Satisfied Customers: 431
Experience:  37 Years Automotive Diagnosis & Repair. Experience with all makes and models..
Type Your Car Question Here...
GM-Frank is online now
A new question is answered every 9 seconds

How do you know if you need to replace wheel bearings, what

This answer was rated:

How do you know if you need to replace wheel bearings, what sound does it make. 1999 trooper 3.5 160,000 miles




Wheel bearings that are failing will tend to make a rumbling-type of noise. This noise ususally changes as you are moving and you apply steering wheel input in one direction an then the other direction. This actually changes the load on the left then on the right wheel bearings, and the rumbling noise should change somewhat as the load on the bearing changes.


Another quick check would be to raise the vehicle,(wheels off of ground) and feel for excess play in the bearings, by grasping the tire/wheel assembly and rock using up and down and side to side force to feel for looseness.


The best way to check the bearings is to actually visually inspect them. The visual inspection is better requested in the form of a "Wheel Bearing Repack".

This involves complete dis-assembly of the assembly. Here's a graphic that details the components.




I hope this information helps


Take Care



Customer: replied 8 years ago.

Thanks for getting back so quick. If everything else seems okay on the trooper dpes it make sense that it would be bearings. Is there anything else I should consider?



Hello again redrider99,

I am assuming that you are hearing some kind of noise that doesn't seem normal, or you wouldn't have asked the question to begin with.


As a matter of fact, you didn't really say you have a noise.


As you are driving, does my description come close to matching your noise?



Customer: replied 8 years ago.

It is a whirling type noise that is very noticeable at higher speed but does show up at the lower speed also. It is not there when you first start up and the truck has been sitting for a short time. The pitch of the sound does change as I change speeds and let up on the pedal. I am going to go out now and see if it changes with the steering as you suggested because I had not paid attention to that. I guess I am worried it's something in the rear end or differential since the trans. is new. And I have not had bearings serviced, So should I do that as a matter of being over due. Thanks for your help.





If the noise is coming from the rear of the vehicle, your description could very well be a pinion bearing type of noise in the rear end.


The information I initially sent was the view of the front. I apologize for missing your note of the noise seeming to be from the rear.


The best way to check for that type of a bearing noise, is to hoist the vehicle and put it in gear running it while in the air...then you can listen to it with a stethiscope.


Upon reading your question to begin with, I make the assumption that you were referring to a bearing type of noise in a wheel bearing. And I also assumed that you were referring to a front wheel bearing type of noise.


If the noise seems to be coming from the rear, then you may or may not notice a difference loading the truck by steering side to side while driving.


Although, if there is a rear wheel bearing failing, you may notice a difference.


I sincerely XXXXX XXXXX information I have provided helps in your diagnosis.


Thank You



GM-Frank and other Car Specialists are ready to help you


By the way,


The front wheel bearing repack is a regular maint. Item, and may be due anyway...but as we chat, I'm leaning toward a pinion bearing in the differential. There is no service other than replacement on the pinion bearings.


Naturally, you'll want to be sure the rear end has the correct level and viscosity of lubricating fluid.


I'm thinking the one thru six on the graphic.



Rear Differential Specifications
Ambient Temperature Lubricant / Viscocity
Note: Limited Slip: Use Addative Part # XXXXX
Below 50 deg. F GL5 - SAE 80w or 80w/90
0 deg. F - 90 deg F GL5 - SAE 90w or 80w/90
Above 50 deg. F Consistently GL5 - SAE 140w




Related Car Questions