Is this differential noise a problem?

[sctrsk]

All:

A while back on a 100F day I was driving my 99 on the highway. I have duratracs and they generally moan/whine around 60+, but this day the sound was resonating really loudly from the back. It seemed to do it more when I was in a turn too. I got spooked it was the rear end, but on a cooler day it didn't do it again. I don't know if the pressure in the tires was higher because they were so hot, or if the diff oil thinned and it was some combination of the pumpkin/wheel bearings.

It's been fine since, and there's no excessive play in anything. I jacked it up and gave one of the wheels a good spin and got this sound from the differential. Can anyone tell me if she's about to blow? I was planning on a 1000 mile trip in a month and probably don't have time to get my other locker rear end rebuilt before then.

The diff oil is a good level and golden clean even after 3000 miles.

How screwed am I?


This is the video
imgur: 4runner diff noise

 

[nevada]

put it in neutral and spin both tires the same direction. any noise?

 

[sctrsk]

this was transfer case in neutral and spinning one wheel the other naturally spun backwards because its an open diff. If I want to spin them together I'll need a helper on the other side but I can probably find someone. If the noise goes away when they spin together does that mean everything is fine?

 

[APhelps]

I'd really not trust that differential on a long trip. Go to a junkyard and pull an entire 3rd member.

 

[nevada]

this was transfer case in neutral and spinning one wheel the other naturally spun backwards because its an open diff. If I want to spin them together I'll need a helper on the other side but I can probably find someone. If the noise goes away when they spin together does that mean everything is fine?

it would indicate a possible issue with the spider gears.
when going straight, both axles are spinning the same speed, so neither spider gear is spinning. when turning, they will be. it sounds like unloaded spider gear noise, BUT typically you do NOT hear that when loaded(vehicle on the ground) nor when actually driving.




its hard to say "it will be fine" from the short video.
if it were me, I would want to visually check the gears. you can have the 3rd out in a couple hours if you take your time.


finding another correct ratio 3rd(assuming its the stock ratio) shouldn't be too difficult, nor expensive. in case you discover that there is something damaged internally..

 

[dogtail]

I had a noise like this and I thought it was in the rear end, it was actually resonating from the Tcase and going to the 3rd member. I know you said you had it in neutral, but it may be from a gear on the back end of the Tcase.
If you pull out the drive shaft you'll rule it out quick.

 

[BoomerBob]

I had a noise like this and I thought it was in the rear end, it was actually resonating from the Tcase and going to the 3rd member. I know you said you had it in neutral, but it may be from a gear on the back end of the Tcase.
If you pull out the drive shaft you'll rule it out quick.

Amazing how sound can travel through metal like that.