Tow Vehicle Rearend Noise 3500 Chev Dually

Rusty Davenport · 06-28-2007, 02:04 PM

Chevrolet 3500 series dually, 2000 year model 7.4 engine---GM rearend 4.10 ratio---owners manual says it requires synthetic rear end grease when replacing. I'm hearing a high pitch "sing" between 60 and 65 mph...just enough to get your attention if the CD player is not loud enough, 40,000 actual miles, is there an additive that might help this and is there any need for alarm outside of just an annoyance ????

Mark Ruset · 06-28-2007, 02:47 PM

Rusty anytime you here a noise that wasn't there before it is a cause for concern. You can do a little diagnosis yourself first. Try driving the truck at the speed the noise is most noticeable than moving the streering wheel back and forth and see if you can change the noise . That will indicate a wheel bearing or side carrier bearing problem. Then left off on the throttle and accelerate if the noise changes you may have a pinipn bearing or ring and pinion concern. I don't believe in snake oils to fix noises. Better off and have it looked at.

Rusty Davenport · 06-28-2007, 04:56 PM

it makes this "singing" during "load" or acceleration periods.

Mark Ruset · 06-28-2007, 05:07 PM

If luck is on your side it sounds like the front pinion bearing. Get the rear cover off and look for any signs of metal flakes in the oil. Do a disassemble of the differential looking at the races and bearings closely. Replace them as necessary. Make sure you use the correct synthetic oil upon completetion. As far as noises in rear axles go, it won't get any better by ignoring them.

76 RACER · 06-30-2007, 02:03 AM

I have a 96 GMC 3500 and I had the exact same problem. The small pinion support bearing went south. Never knew there was a problem with it until I got to approx. 72 - 75 mph and was getting a strange small vibration. I believe all those rear ends in that time period had a small whine to them anyway. I know a few guys that have complained about the same deal. If you catch it quick enough you havent ruined any of the other bearings in the housing. I didnt take mine to a dealer to have it fixed. The prices were outta sight. Went to a truck repair shop. Freightliner dealer took care of it nicely and saved some bucks!

Bob Mulry · 06-30-2007, 03:37 AM

Do yourself a favor, if you are going to do the repair yourself, check and record the backlash so the ring and pinion will go back into the same wear pattern. If you don?t set the backlash to the original number that you had before disassembly you will end up with a VERY NOISY rear end.

Use the same pinion shim so you also have the correct location for the pinion in relation to the ring gear.

Just a heads up,
Bob

06-28-2007, 02:04 PM	#1
Rusty Davenport Senior Member Join Date: Jun 2005 Location: Nashville N.C. Posts: 505 Likes: 4 Liked 100 Times in 26 Posts	Tow Vehicle Rearend Noise 3500 Chev Dually Chevrolet 3500 series dually, 2000 year model 7.4 engine---GM rearend 4.10 ratio---owners manual says it requires synthetic rear end grease when replacing. I'm hearing a high pitch "sing" between 60 and 65 mph...just enough to get your attention if the CD player is not loud enough, 40,000 actual miles, is there an additive that might help this and is there any need for alarm outside of just an annoyance ????

06-28-2007, 02:47 PM	#2
Mark Ruset Member Join Date: May 2006 Location: Southwest Florida Posts: 250 Likes: 23 Liked 34 Times in 24 Posts	Rusty anytime you here a noise that wasn't there before it is a cause for concern. You can do a little diagnosis yourself first. Try driving the truck at the speed the noise is most noticeable than moving the streering wheel back and forth and see if you can change the noise . That will indicate a wheel bearing or side carrier bearing problem. Then left off on the throttle and accelerate if the noise changes you may have a pinipn bearing or ring and pinion concern. I don't believe in snake oils to fix noises. Better off and have it looked at. __________________ Mark Ruset 2048 STK

06-28-2007, 05:07 PM	#4
Mark Ruset Member Join Date: May 2006 Location: Southwest Florida Posts: 250 Likes: 23 Liked 34 Times in 24 Posts	If luck is on your side it sounds like the front pinion bearing. Get the rear cover off and look for any signs of metal flakes in the oil. Do a disassemble of the differential looking at the races and bearings closely. Replace them as necessary. Make sure you use the correct synthetic oil upon completetion. As far as noises in rear axles go, it won't get any better by ignoring them. __________________ Mark Ruset 2048 STK

06-30-2007, 02:03 AM	#5
76 RACER Member Join Date: Mar 2007 Posts: 247 Likes: 0 Liked 0 Times in 0 Posts	Re: Tow Vehicle Rearend Noise 3500 Chev Dually I have a 96 GMC 3500 and I had the exact same problem. The small pinion support bearing went south. Never knew there was a problem with it until I got to approx. 72 - 75 mph and was getting a strange small vibration. I believe all those rear ends in that time period had a small whine to them anyway. I know a few guys that have complained about the same deal. If you catch it quick enough you havent ruined any of the other bearings in the housing. I didnt take mine to a dealer to have it fixed. The prices were outta sight. Went to a truck repair shop. Freightliner dealer took care of it nicely and saved some bucks!

06-30-2007, 03:37 AM	#6
Bob Mulry VIP Member Join Date: Apr 2002 Location: Coarsegold, CA Posts: 1,017 Likes: 57 Liked 321 Times in 101 Posts	Re: Tow Vehicle Rearend Noise 3500 Chev Dually Do yourself a favor, if you are going to do the repair yourself, check and record the backlash so the ring and pinion will go back into the same wear pattern. If you don?t set the backlash to the original number that you had before disassembly you will end up with a VERY NOISY rear end. Use the same pinion shim so you also have the correct location for the pinion in relation to the ring gear. Just a heads up, Bob __________________ Bob Mulry 7516 STK A & M Motorsports

06-28-2007, 04:56 PM	#3
Rusty Davenport Senior Member Join Date: Jun 2005 Location: Nashville N.C. Posts: 505 Likes: 4 Liked 100 Times in 26 Posts	it makes this "singing" during "load" or acceleration periods.