go an 02 silverado z71. sometimes at low speed i hear a sight rotaional noise. sometimes a howl. more noticable turning on an onramp. it is not realy loud have to lisen for it. just replaced the frt axle seals. what could it be or is it normal for a little noise in frt diff. in 4hi. it defnatly sounds rotational. thanks for the help.

 

Im willing to bet its a front hub... Does it make the sound when turning both ways???

 

its not there in 2 hi though.

 

it now has a hum when slowing down in 4 hi. at slow speeds what could this be bearrings ujoint drive shafts. backlash in diff. thanks for help.

 

Do you use 4wd much???? With out having wear on the gears they will make a humming noise..

The other thing it could be is the carrier bearings..The older front diff's are known for the bearings going out..When did you change the fluid last???

 

The front diffs are also known for the carrier bearing retainers breaking causing the front carrier to rock around in the housing and the bearings to eat themselves...I believe that if it's left alone too long the ring and pinion will also sustain damage

 

Mine makes the same noise. (all 4 of my gm's made that noise)

Its normal.

How fast are you traveling in 4wd? And hopefully only on snow covered roads.

 

My noise isn't normal, it's coupled with a handful of metal on the front diff drain plug, although some extra noise is to be expected in 4wd, it just depends on how much noise the OP is experiencing. My noise got progressively louder as time went on. I recommend that the OP pull the drain plug and check for excessive metal shavings.

 

its when slowing down less than 40km. sometimes a little on hiway.