To fix or not to fix: front differential whine? (1 Viewer)

Joined
May 30, 2010
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Arlington, Texas
I am set to do the front axle service this week. This seems like a good time to address any front differential problems. I've had a noticeable (but not loud) whine under load at 50-70 mph for the last 10k miles or so. It really hasn't gotten any louder/worse during that time (more or less a year). The whine appeared AFTER I changed out the front diff oil after I bought the truck--the old stuff was thick with moly (I also changed out the center and rear diff oil, engine and transmission at the time). Finally pulled the front DS and locked the center diff and went for a test drive: the whine is gone. Since the whine hasn't been getting any louder over the last 10k mi/year, is there really any reason to pull the diff and replace the pinion bearings? I can live with the slight noise. I've lived with it for a year now and the truck doesn't seem to be any worse for wear. I couldn't find any play at the pinion flange, but there isn't much, if any, preload. Truck has 180k+.
 
Joined
Dec 10, 2007
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7,621
I have the exact same issue but when I removed the front DS the howl under load remained (10-30 then 50+mph), so it's the rear diff in my case. Different sources say howl under load is either the front or rear pinion bearing. If the front bearing then the diff doesn't have to come out, but most say replace both pinion bearings, IDK. One reference said to try tightening up the pinion nut a tad (like 1/4 inch) to increase the preload but most say don't do it. Also read that over time the ring and pinion will develop an abnormal wear pattern if the bearings are loose so when you do go to rebuild the diff you may also have to replace them both along with new bearings??
 
Joined
Apr 5, 2011
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Honolulu, HI
I say replace the pinion bearings since you're taking the axles out. Kill two birds with one stone if you know what I mean. That's what I did.
You don't want to take the axle apart again if the whining gets worse later on and you certainly don't want the diff to blow if the bearings lock up. Bearings do go bad, they don't get better.
 
Joined
Dec 10, 2007
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kaveeks: can you describe how you replaced the bearings and set preload? Start a new thread maybe?
 
Joined
Apr 5, 2011
Messages
187
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Honolulu, HI
I did not do it myself. I had a local indy mech do it who specializes in yota 4x4s. You can remove the third after you pull the axles out and then bring it to a shop.
 

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