Noisy differential after fluid change

[slowdime]

So, like the title says, I changed the differential oil in my s10 a week or so ago and I've noticed it is much louder than it was before the fluid change. It's not really loud but it's noticeable in the cab. It's a non limited slip diff and the owners manual calls for 80w-90 gear oil which is exactly what I put in. The level is correct and I gave the internals a good spray down with brake cleaner and let dry before I put the cover back on
It's worth mentioning that this noise--kind of a whirring sound- goes away once I've been driving for around 10 minutes or so and it's warmed up.

 

[domer10]

Try putting in a friction modifier. Should help.

 

[gathermewool]

Originally Posted By: domer10
Try putting in a friction modifier. Should help.


Is there a reason you recommend this for an open diff?

I wonder if the brake cleaner has anything to do with this.

 

[antiqueshell]

Originally Posted By: gathermewool
Originally Posted By: domer10
Try putting in a friction modifier. Should help.


Is there a reason you recommend this for an open diff?

I wonder if the brake cleaner has anything to do with this.



That's my guess, why in the world would you spray a solvent in there? LOL

 

[clinebarger]

It most likely was already making noise, I have seen this to often to count, You serviced it...Now your listening to it.

 

[GutsyGecko]

Ignore it. I've nuked diffs with brake cleaner all my life. It doesn't matter.

 

[slowdime]

Originally Posted By: clinebarger
It most likely was already making noise, I have seen this to often to count, You serviced it...Now your listening to it.

Probably right. It wasn't something I noticed til I changed the fluid and started listening.

 

[JD4440]

Originally Posted By: GutsyGecko
Ignore it. I've nuked diffs with brake cleaner all my life. It doesn't matter.

On my 97 it had a coating of black in it. I used a can of brake cleaner and let it dry for a while, no problems here either.

 

[friendly_jacek]

was the old fluid like a silver paint?

 

[Merkava_4]

Originally Posted By: domer10
Try putting in a friction modifier. Should help.


Does the friction modifier help the oil stick to the gears better? How's it work?

 

[slowdime]

No it just looked like old oil. Some gunk came out after I sprayed it with the brake cleaner and I gave it a good wipe down. The gears all looked ok from what I could see.

 

[901Memphis]

Did you service the previous fill? Maybe what you drained out was thicker than recommended or thicker from oxidation and made less noise.

 

[friendly_jacek]

Originally Posted By: slowdime
No it just looked like old oil. Some gunk came out after I sprayed it with the brake cleaner and I gave it a good wipe down. The gears all looked ok from what I could see.


Good. Once I serviced both diffs in a subaru and used (OEM) oil looked like silver paint. Sure enough, rear diff become noisy with the new Redline 75W90. The car got wrecked at 60,000 miles so no long term followup.

 

[slowdime]

Nope. Previous fill was done by the last owner. Not sure what he used but I put in the factory specced 80w-90 with no additives. As was mentioned earlier, it may have been a little noisy before I changed it but just never noticed until I listened for noise after I changed the fluid. I'm kind of wishing I'd spent a bit more to get some amsoil svg but I'm a poor working college student so the store brand was all I could afford, I checked who made it and it was valvoline.

 

[artificialist]

When you blast gears with brake cleaner, the majority of the cleaner washes out of the differential. Whatever hasn't drained out will evaporate in 15 minutes, causing little to no chemical contamination to the new gear oil. There may still be a little wear metal behind, but nothing to worry about.

I prefer differentials with pan gaskets because it is easy to remove the gray slime which is loaded with wear metal. In differentials that only have a drain plug and fill plug, changing the oil early, and then changing the second fill early seems like the only way of removing that gray slime.

 

[Bgallagher]

I believe lubeguard makes an additive for diffs. Give that a try. Sounds to me like the gunk that you cleaned off was probably quieting a worn gear or something.