Whining Noise Taking off while in A4WD and 4WD

CaptainXL

Original poster
Member
Dec 4, 2011
2,445
Does anyone know if a slight whining noise in 4WD while accelerating from a stop is normal for our vehicles? It's something that's always been there since I bought the truck a few years ago. It sounds like something spooling up and is proportional to whatever gear I am in. It's basically the whining noise you hear when in 4WD low but much quieter.
 

TangoBravo

Member
Dec 5, 2011
208
My TB doesn't do that. When is the last time the front diff and Tcase fluid has been changed?
 

CaptainXL

Original poster
Member
Dec 4, 2011
2,445
TangoBravo said:
My TB doesn't do that.

Which part? No whining in A4WD or no whining in 4WD low or no whining in both?


TangoBravo said:
When is the last time the front diff and Tcase fluid has been changed?

Changed transfer case in February 2011. The fluid that came out was green not blue. Wasn't black at all. The transfer case has been symptom free otherwise.

Front diff was black and probably never done. Was a bear to remove inspection cap.
 

northcreek

Member
Jan 15, 2012
3,315
WNY
CaptainXL said:
Does anyone know if a slight whining noise in 4WD while accelerating from a stop is normal for our vehicles? It's something that's always been there since I bought the truck a few years ago. It sounds like something spooling up and is proportional to whatever gear I am in. It's basically the whining noise you hear when in 4WD low but much quieter.

Mine does it too and it has never gotten any worse.My fluids are proper and current.I'm now thinking that a slight variation in tire size or road crown might cause the spider gears to work and create a gear noise.I say this because on dry pavement in 4wheel I have a slight pull to the right, in snow conditions I do not perceive a noise or pull.Just a theory but,no one has come up with anything better so far and I'm living with it and doing fine:thumbsup:Mike.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
northcreek said:
...I'm now thinking that a slight variation in tire size or road crown might cause the spider gears to work and create a gear noise....
I had to have it explained to me by James Downing, but the front spider gears are spinning in 2HI mode. The driver's side CV shaft is always spinning because there's no disconnect in its hub. So the end gear on its shaft is rotating, but the carrier in the diff is not. So the spider gears transfer the driver's end gear rotation over to the passenger side, where the intermediate shaft rotates backwards. What changes in 4HI mode is the front driveshaft starts being turned by the transfer case, then the diff carrier starts rotating, and the spider gears actually stop rotating on their axes as long as the two front wheels are at the same speed (going straight).
 

northcreek

Member
Jan 15, 2012
3,315
WNY
the roadie said:
I had to have it explained to me by James Downing, but the front spider gears are spinning in 2HI mode. The driver's side CV shaft is always spinning because there's no disconnect in its hub. So the end gear on its shaft is rotating, but the carrier in the diff is not. So the spider gears transfer the driver's end gear rotation over to the passenger side, where the intermediate shaft rotates backwards. What changes in 4HI mode is the front driveshaft starts being turned by the transfer case, then the diff carrier starts rotating, and the spider gears actually stop rotating on their axes as long as the two front wheels are at the same speed (going straight).

Interesting...makes you wonder why they even bothered with a disconnect,other than a little less rotating mass and oil drag why bother? it isn't like these riggs were close to winning the Mobil economy run:undecided:
 

RayVoy

Member
Nov 20, 2011
939
the roadie said:
I had to have it explained to me by James Downing, but the front spider gears are spinning in 2HI mode. The driver's side CV shaft is always spinning because there's no disconnect in its hub. So the end gear on its shaft is rotating, but the carrier in the diff is not. So the spider gears transfer the driver's end gear rotation over to the passenger side, where the intermediate shaft rotates backwards. What changes in 4HI mode is the front driveshaft starts being turned by the transfer case, then the diff carrier starts rotating, and the spider gears actually stop rotating on their axes as long as the two front wheels are at the same speed (going straight).
Yeah, that's way turning one whell of a rear drive car/truck, when both rears are off the ground, will cause the other wheel to turn in the opposite direction (assuming the tranny is in neutral).
 

northcreek

Member
Jan 15, 2012
3,315
WNY
RayVoy said:
Yeah, that's way turning one whell of a rear drive car/truck, when both rears are off the ground, will cause the other wheel to turn in the opposite direction (assuming the tranny is in neutral).

(And not positraction):biggrin:
 

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