Whine noise coming from rear end?

[tnmotown]

The sound has been gradually getting noisier after time. I'm thinking it's coming from the rear-end somewhere? No leaks underneath, I tried shifting gears manually while driving to see if was transmission and it wasn't. My tires are almost 2 years old with maybe 70% left, and they are the same brand from last time which never made any noise. So.... maybe bearings?


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[pacofortacos]

Sounds like a bearing went bad in the rearend. That or you don't have any oil in it.

 

[tnmotown]

Sounds like a bearing went bad in the rearend. That or you don't have any oil

Sounds like a bearing went bad in the rearend. That or you don't have any oil in it.

Must be a bearing then. I did a fluid change about 3 months ago, the diff housing is bone dry

 

[pacofortacos]

Usually the pinion bearings but it could be the carrier bearings also.

How did the oil look when you changed it?

 

[Burla]

Must be a bearing then. I did a fluid change about 3 months ago, the diff housing is bone dry

I'm guessing you mean outside of housing.

What fluid did you use brand a weight and how soon after the change did the whine start?

 

[tnmotown]

Usually the pinion bearings but it could be the carrier bearings also.

How did the oil look when you changed it?

It seemed a bit gold and sparkly i guess? It was a little hard to see as I had to do it outside in the dark with just a flashlight.

 

[tnmotown]

I'm guessing you mean outside of housing.

What fluid did you use brand a weight and how soon after the change did the whine start?

Correct, outside the housing it is bone dry.

The whine was there before I did the fluid change, but wasn't as noisy as it is now. It's slowly progressively getting higher pitched sound.

It was Lucas oil that I used, if I remember correctly I want to say it was 85w-90.

 

[Burla]

Probably the two worse fluids you can use are lucas or RP for diffs, study posted in syn thread. And the correct weight is 75w140 if you have a 1500? Might want try that weight in amsoil or redline. So you have any idea what fluid was in there when whine started?

 

[Burla]

study on gear fluids pdf.

good luck with it, burla

lucas was dead last in test
mopar was second to last
royal purple was third to last

 

[tnmotown]

No I do not know what fluid was in it before I drained it out.

Mileage was probably around 55k miles at time of diff fluid change, who knows if that was original fluid or if previous owner done it before. This is the first time I’ve done it in my ownership and I bought truck with 28k miles on it.

 

[tnmotown]

Pulled the cover off and didn't really see any metal shavings or stuff like that. All the teeth seem to still be in tact. I did notice at the end of the axle where the c-clip inserts, it is discolored and blue, could that be a concern?

Anyways, I'm going to get some 75w-140 amsoil and fill it back up. Hopefully it makes a little bit of a difference. Seems like I'll need to be saving up for a rebuild soon...

 

[Burla]

Read the PDF, note the corresion test, Lucas is as bad as it gets. But, I don't think it was in long enough to have any issues, that little varnish isn't any concern, certainly isnt your whine. Just read that pdf and carry the knowledge forward, there are some gear fluids nobody should buy ever. The larger problem is the fact that the diff is clean, so literally the hope will be is the increased film strength gonna help a whine. If it was dirty, there would be more of a chance it would fix it, but now all you can do is wait til you get the good stuff in there.

 

[pacofortacos]

It seemed a bit gold and sparkly i guess? It was a little hard to see as I had to do it outside in the dark with just a flashlight.

Really shouldn't be sparkly, often times that is metal. It really doesn't matter now, it's time to replace the bearing and I would do pinion and carrier and closely look at the end axle bearing - though those are usually ok.

I prefer Redline gear oil as I have had it survive where others haven't - wasn't in a car though.