9.75" Gear Noise Resolved!
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Joined: Feb 2002
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From: Newark,CA
9.75" Gear Noise Resolved!
I have been fighting to get a set of 4.10's in my truck that don't make some amount of noise. I have corresponded with three others who have the same complaint. Usually not a prob in a 4x4 due to transfer case and tire noise. I have returned two sets to two different manufacturers because the noise level was unacceptable. I have the third set in now and have added and removed shims four times to find the best setting and have found a point where the noise level is acceptable.
HERE IS WHAT I FOUND OUT TODAY.
I called the three domestic manufacturers of gears for this rear end. I asked to speak to their best gear guru and introduced myself as a customer looking for quiet gears. They all essentially responded with the same statement.
The 9.75" rear axle is a heavy duty unit designed for truck durability not as a passenger car unit. As a result once you get past 3.55 ratio they tend to become noisy. True, my OEM 3.55's had a slight whine even after the dealership replaced the gears and ALL bearings under warranty.
If I demanded absolutely noise free gears, they all said "we can't guarantee your satisfaction".
SO, the gears I have now are US Gear. They used to be sold through Ford Motorsports and though the engineer wouldn't say it, I believe Motorsports stopped selling them because they had too many noise complaints.
After thinking about the situation, I decided "why an I so concerned about a little whine from the rear when tomorrow I am going to start installation of an ATI ProCharger". From what I have read, the whine from it will easily drown out the rear whine. CASE CLOSED (well almost).
If, in the future, I decide I need absolutely silent 4.10's I'll throw a Nodular Case 9" in the sumbich, Ha!
HERE IS WHAT I FOUND OUT TODAY.
I called the three domestic manufacturers of gears for this rear end. I asked to speak to their best gear guru and introduced myself as a customer looking for quiet gears. They all essentially responded with the same statement.
The 9.75" rear axle is a heavy duty unit designed for truck durability not as a passenger car unit. As a result once you get past 3.55 ratio they tend to become noisy. True, my OEM 3.55's had a slight whine even after the dealership replaced the gears and ALL bearings under warranty.
If I demanded absolutely noise free gears, they all said "we can't guarantee your satisfaction".
SO, the gears I have now are US Gear. They used to be sold through Ford Motorsports and though the engineer wouldn't say it, I believe Motorsports stopped selling them because they had too many noise complaints.
After thinking about the situation, I decided "why an I so concerned about a little whine from the rear when tomorrow I am going to start installation of an ATI ProCharger". From what I have read, the whine from it will easily drown out the rear whine. CASE CLOSED (well almost).
If, in the future, I decide I need absolutely silent 4.10's I'll throw a Nodular Case 9" in the sumbich, Ha!
