Rear end gear noise

[Tbdo]

My differential is making a whining sound at 50-70 mph while accelerating. The axle assy is a Dana 30. The gears are 4.30 but are not new. The differential guy I used said the gears were a little worn but are fine, so he did the setup. I'm running Shell Rotella 85w-140 now. Should I go to a straight SAE 140 like Sta-Lube GL-4 Hypoid Gear Oil?
Thanks
Maury
[email protected]

 

[Jason2007]

Since they are used gears, the pattern is already cut in those gears from the previous install. Now, they are in your rear end which is why there is noise. A thicker oil may reduce it but it will not eliminate it.

 

[DieselTech]

Gears are making noise because they are worn or the preload is no longer correct. It's not the oil. The minute he said the gears were a little worn they should have been changed..

 

[crazyoildude]

keep the oil the same if he said the gears were a little worn that should be the key

 

[Zaedock]

Originally Posted By: Tbdo
My differential is making a whining sound at 50-70 mph while accelerating. The axle assy is a Dana 30. The gears are 4.30 but are not new. The differential guy I used said the gears were a little worn but are fine, so he did the setup. I'm running Shell Rotella 85w-140 now. Should I go to a straight SAE 140 like Sta-Lube GL-4 Hypoid Gear Oil?
Thanks
Maury
[email protected]


What vehicle? Volvo? Jeepster Commando?

 

[DieselTech]

BTW welcome to BITOG. Where in OK are ya?

 

[Tbdo]

Its in a Volvo 1800E. The differential guy I used (all he does is differentials & transfer cases) said the gears were a little worn but still very good. I guess I'll try Sta-Lube SAE 140 GL-4 Hypoid Gear Oil to reduce the noise although not eliminate it. I saw on mossmotors.com (classic British sports cars) that they use the same SAE 140 hypoid gear oil I mentioned in the differentials. If anyone has any other info on this issue, please chime in.
Thanks
Maury
Owasso OK

 

[SteveSRT8]

I have had limited success with worn diffs by changing oils. It can greatly reduce the noise.

If you're certain it's the gears and not a bearing, I don't think you will be able to stop it.

 

[mechtech2]

So you put a used set of gear in your rear end?
And they were then set up ?
There are preloads for each bearing - specs for new and used.
There are setting for the gear teeth - each gear in and out.
This is finally checked under load by testing the pattern left with special ink to see the loading.
Did he do this?
If he kinda did, you get kinda right results.
If the gears are worn enough to tell, it is tough to set up, an they won't ever be perfect in all situations.
And who knows about your used bearings?

People used to use sawdust in their differentials to quiet them down when they sold a car. So thicker helps with noise.
But if it gets cold where you are, you are going to do damage to your rear end with that straight weight lube.

 

[Tbdo]

The differential guy I used put in new bearings. He said he had to change shims a couple of times to "get it right". Its the gears making the noise. I heard about the sawdust but I'm not going to do that. NAPA has the SAE 140 weight. If its good enough for the Brits, I'll give it a try - Oklahoma is way south of England. A friend of mine that has a Sunbeam Alpine says "What are you whining about?", no pun intended. She says its a radio noise - turn up the radio & the noise goes away. Apparently her car has this whine also. I'll try the 140 oil, if it reduces the noise - good, if not, I've wanted a new car stereo for some time now...
Thanks all
Maury