Whine at 40-43 MPH

[jschunke]

My 2007 Silverado classic 2x4 3.23 gears (2000 mi on the

odometer) has a very noticable whine when it's in 4th gear going

between 40-43 MPH. The whine goes away when the

torque converter locks in at around 43 MPH. My guess

is it's coming from the rear end, but not 100% sure.

Does this seem to be a defect?

[C & A s Dad]

Is it a 4.10 gear truck?

 

My Yuk has a slight whine (you have to be listenting for it) exactly where you are describing and after the dealership svc mgr and a GM rep explained to me it was the 4.10 gears I still was not sure. They pulled the rear end down and inspected everything under warranty and had a real prof rear end guy set it back up properly with all new bearings everywhere including the wheels, carrier and pinion. They also replaced the drive shaft with a redisgned unit that has a balance type device just behind the trans. It is supposed to stop most drive train noise from feeding back up. The slight whine was still there. They then located another truck with 4.10s and let me drive it and guess what, the same noise at the same speed.

 

Mine comes in around 40 to 42 and goes away around 50. Small price to pay for the stump pulling 4.10s.

[jschunke]

It's 2 wheel drive, 3.23 gears, far from a stump puller!

 

The whine I hear is more than faint. It sounds similar to my muncie M22

in third gear, if you know what I mean.

 

Very disappointing. Seems that they didn't cut the gears very well

on the Silverado rear.

[GM-Tech]

Ring and pinion whine *usually* occurs under very specific conditions. The speed is in the right range. 45 mph seems to be the magic number, but it occurs slightly above or below that. And, it happens either on light accel, decel or during steady float. It will almost never occur under more than one of those scenarios. When does yours whine?

[jschunke]

Mr. Tech, It whines more under accelleration.

Diminishes in volume as I let off the gas. Not

noticable under decelleration. It seems to

make less noise when it's hot.

 

I changed the rear diff fluid with 800 miles on the

odometer, then at 2000 miles after hauling a load

from Boston.

 

Some say it's counter-produictive to change the lube

too soon during the break-in period. Wonder if that

has anything to do with it?

[pm26]

I had a rear differential whining problem on my 95 Nissan SE V6 4X4 truck with 4.23:1 (?) gear ratio. The whine originally developed after aboutt 3k m iles and would occur in 45-50 MPH speed range (top gear), but only under load, i.e. when gas pedal was pressed down at steady speed. All whining stopped when I took my foot off the gas pedal.

 

The entire rear differential was replaced under warranty. Unlike GM differential, this one had no rear cover and the pumpkin unbolted in one piece from the axle housing.

The new one was quiet was about 2k miles, and then it started whining, again in the same speed range. The main difference was that this time it only whined when not under load (i.e. foot off the gas pedal and coasting). Under steady load it was quiet at all speeds.

 

They explained to me that this type of noise was directly related to differential gear backlash setting, which is done by shimming. Gear ratio has absolutely nothing to do with this noise. It has to do with the play between gear teeth which can be adjusted by shimming.

 

I stayed with the second differential because the noise only occured upon coasting and it was a lot less objectionable. Heavy weight gear oil (90W 140) did quiet the differential quite a bit.

 

I know from experience that these types of noises can be very annoying, as one tends to get obsessed with them.

 

But once again, these noises are not necessarily normal. My Chevy truck differential is quiet under all conditions. And believe me, after the experience with Nissan, I would notice it right away.

[GM-Tech]

Diminishes in volume as I let off the gas. Not noticable under decelleration.

 

Letting off the gas and decelerating is the same thing. When you let off the gas, it decelerates, doesn't it?

 

I don't see why you wasted your money changing the fluid, but I don't see it being any sort of problem as long as you used the correct lube.

[GM-Tech]

They explained to me that this type of noise was directly related to differential gear backlash setting, which is done by shimming.  Gear ratio has absolutely nothing to do with this noise.  It has to do with the play between gear teeth which can be adjusted by shimming.

 

This is basically correct though you need to throw pinion depth into the settings that can affect this noise too. Ratio should have no bearing on noise.

[C & A s Dad]

GM Tech, when you say ratio should have no bearing on noise, I would agree wtih you. I am not sure if the my GM Service Mgr and the GM Rep were trying to comfort me or not, but they were atoment that the lower gears (mine are 4.10s) would create some additional noise. Again, this may have been their way of making me feel that my truck was normal. I will say, the other one I drove, had the exact same slight whine around 45. Either way, it never got any worse or better and I learned to live with it and do not even hear it any more.

[California Flash]

My 2007 Silverado classic 2x4 3.23 gears (2000 mi on the

odometer) has a very noticable whine when it's in 4th gear going

between 40-43 MPH. The whine goes away when the

torque converter locks in at around 43 MPH. My guess

is it's coming from the rear end, but not 100% sure.

Does this seem to be a defect?

 

<{POST_SNAPBACK}>

 

 

 

Noise from the differential is caused by improper contact between the pinion gear and ring gear.

 

The gear ratio has nothing to do with noise.

 

All differentials will exhibit some noise. Most people will not find it objectionable. However, it can reach levels where it is intolerable and can be heard by most drivers.

 

The noise can be during acceleration, deceleration, or when floating between the drive and coast sides of the gears. Noise can occur at any speed, but generally will happen between 40 and 70 miles per hour.

 

Proper diagnosis involves coating the ring gear with a special gear paste and then rotating the differential gears several times. After rotation, the contact patch between the gears is observed for proper position.

 

An experienced mechanic would then either adjust the pinion shims if the pattern is either low or high. A contact patch toward the toe or heel end of the ring gear indicates to little or excessive gear lash which is corrected by changing the shims controlling the position of the differential case.

 

Most manufacturers will rate the noise as commercial and will not cover it under warranty without a fight.

 

If you feel the noise is excessive, press the dealer, zone rep, customer service or higher corporate management for correction under warranty.