Rear end whine

[1996ex]

The rear differential on my 2003 has been whining at highway speeds for a year or two. It's not terribly loud, but how safe is it to drive with it like this?

How much does it cost to rebuild the rear end on a 4.0?

Thank you!

 

[Mr. Alligator]

Change your differential fluid. Include limited slip additive, if required. Make sure you have adequate fluid.

When you have cover off, check differential for metal shavings and flakes.

This is very unlikely to be a dangerous condition, unless you find obvious problems during fluid change.
It also should last for tens of thousands of miles.

Good Luck.

 

[1996ex]

Change your differential fluid. Include limited slip additive, if required. Make sure you have adequate fluid.

When you have cover off, check differential for metal shavings and flakes.

This is very unlikely to be a dangerous condition, unless you find obvious problems during fluid change.
It also should last for tens of thousands of miles.

Good Luck.

Thanks! I've actually never changed rear diff fluid before. I assume it just involves loosening the cover to drain the fluid, removing the cover to inspect it, putting a new gasket on when I re-install the cover, and then filling it via the hole at the top?

I'm picturing a solid rear axle-type rear end, purely because I used to have Jeep Grand Cherokees.

 

[imp]

The rear differential on my 2003 has been whining at highway speeds for a year or two. It's not terribly loud, but how safe is it to drive with it like this?

How much does it cost to rebuild the rear end on a 4.0?

Thank you!

I had a whine-like noise which I was certain came from the gears. Drove it thousands of miles, finally the noise becoming scary enough to look into it.

With all four wheels off the ground (4X4), running at idle in drive (4X4 HIGH), my stethoscope, a big long screwdriver, indicated most intense sound out at left wheel bearing, not in center-section.

Below a pic of the bearing outer race, showing spalled surface:

 

[Mr. Alligator]

You got it.

Make sure you remove the fill plug (3/8 inch square socket drive) before you remove the cover. The fill hole is hidden on the top/side of the differential. This will help you avoid the disaster of removing the fluid, and not being able to refill the fluid.

It might help give you more space to work if you remove the spare tire. Nothing smells quite like worn out gear oil.

Good Luck.

 

[Mr. Alligator]

Isolating these noises, as @imp stated, is essential to resolution. But with 20 years of use, I would change the rear differential fluid and inspect the differential in any case.

 

[1996ex]

Isolating these noises, as @imp stated, is essential to resolution. But with 20 years of use, I would change the rear differential fluid and inspect the differential in any case.

Thanks for your help, I was honestly just going to call around and bring it in somewhere! I didn't think that changing the fluid might help! Simple enough job though.

 

[Mr. Alligator]

It is good maintenance and a good project regardless.

 

[chris8428]

Hi

I just changed the rear differential fluid and transfer case fluid on my 2005 this past weekend. Here are some threads I found helpful.

Changing Differential Fluids

Going to hopefully change the front and rear differential lube this weekend. My Hayne's has the rear needing about 1.5qts, but mentions nothing about the front differential. Can anyone guess as to how much fluid is in the front? Cornburner, you used 75W-140 in both right? Any real benefit...

www.explorerforum.com

Changing Differential Fluids

Going to hopefully change the front and rear differential lube this weekend. My Hayne's has the rear needing about 1.5qts, but mentions nothing about the front differential. Can anyone guess as to how much fluid is in the front? Cornburner, you used 75W-140 in both right? Any real benefit...

www.explorerforum.com

Not to hijack this thread, but the only thing that seems to be up for debate as you read through these threads is the level of fluid when you refill the rear differential. Most people say to fill the differential up to where it runs out of the fill hole. This will be about 1.5 quarts or so. Others say to do this and then add another 8 ounces through the speed sensor at the top of the differential.

When I first changed my fluid years ago the differential from the factory was only full to the top of the fill hole. Every time I have changed it since this is the level fill to. This has worked for 167,x.. miles.

Anyway just FYI as you read through.