Rear noise at 40-60MPH

Good morning,

It sounds like a bearing failure in the differential itself. You have axle bearings, pinion bearings, and carrier bearings. I attached a picture for you to view.

https://www.2carpros.com/articles/how-a-differential-works

https://www.2carpros.com/articles/differential-service

This could be caused by low oil levels or not changing the oil regularly.

In most cases, it is cheaper to replace the entire differential assembly with a used unit instead of rebuilding the old one. It can get very pricey to rebuild the assembly.

Roy

Thanks for the quick response! So, should I begin with doing a differential fluid change and see what that does first? Or does the howling sound indicate that the differential assembly is pretty much done?

Changing the oil will not do anything about the noise. The damage has already been done.

I would start looking for a differential assembly at a junkyard. There should be a tag on the cover of the rear of the car. You will need that tag with the numbers to match up the correct part.



Roy

What is the approximate repair cost for this type of job?

The differential assembly is around $500.00.

The labor is 8 hours at $150.00 per hour.

$1,500.00 to $2,00.000 for the job.

Roy

Just to confirm, is it optimal to just replace only the third member (pumpkin) or are you indicating that it’s best to replace the entire rear mechanical assembly such as the axle shafts and third member all together?

You should also do the axle bearings as well. The pumpkin is mandatory, yes.

I would do it right.

Roy

Thank you for your help!

You are welcome.

Always glad to help.

Roy

Let me know if you have any other questions.

Roy

Just one more question. If I replace the entire assembly, the replacement unit would also need to have the locking differential function I’m assuming.

Correct, in order for it to work correctly.

Roy