Yes its another gear thread. but I need help PLEASE

03sonikblu · November 15th, 2011, 10:01 PM

Ok so I installed 4.10 gears, 31 spline axles, and a cobra diff in my car about 15k miles ago, the problem is that Im starting to get gear noise on decel and I was wondering other than a rebuild is there anything that I can do. It always made noise but its nothing like what it has been and its progressively getting worse.

brokenweasel · November 15th, 2011, 10:26 PM

15k, change the fluid and see what happens?

bulloch27 · November 16th, 2011, 01:09 AM

That is typically caused by inadequate pinion preload or the pinion nut backing off (which would also be lack of preload). Remove the driveshaft flange and hit the pinion nut with an impact and the noise will most likely vanish.

03sonikblu · November 16th, 2011, 02:36 AM

Originally Posted by bulloch27

That is typically caused by inadequate pinion preload or the pinion nut backing off (which would also be lack of preload). Remove the driveshaft flange and hit the pinion nut with an impact and the noise will most likely vanish.

Ok, is there any down fall to doing this, something negative that would come of it? I would rather deal with the noise for now than make a big problem bigger.

03sonikblu · November 16th, 2011, 02:36 AM

And if I were to hit it with an impact how much should I tighten it?

Nitmare67 · November 16th, 2011, 02:38 AM

You may get the pinion too tight increasing the pinion bearing preload and burning it up. Change the oil and check the backlash while your in there. Also check for pinion movement. The good thing is 90% of the time you will get noise but no wear. Its just harmonics.

03sonikblu · November 16th, 2011, 01:55 PM

Originally Posted by Nitmare67

You may get the pinion too tight increasing the pinion bearing preload and burning it up. Change the oil and check the backlash while your in there. Also check for pinion movement. The good thing is 90% of the time you will get noise but no wear. Its just harmonics.

Well that is good to hear, I will go out and check everything and let you know what I find. If my memory serves me correctly backlash is the space between the pinion gear and the ring gear, correct?

gdl · November 16th, 2011, 10:13 PM

You measure backlash by holding the pinion gear still and then use a dial indicator to measure how much the ring gear moves when you rock it back and forth. Bulloch's right though, noise on decel is a sign of inadequate preload on the pinion bearing. I'd do what he says but maybe sneak up on it, hit it with the impact for just a few seconds, put it back together, go for a drive and see if it's better. If not, do it again.

November 15th, 2011, 10:01 PM	#1
03sonikblu Regular 2003 GT Join Date: Aug 2010 Location: Orange County, CA Posts: 203 iTrader: 0 reviews	Yes its another gear thread. but I need help PLEASE Ok so I installed 4.10 gears, 31 spline axles, and a cobra diff in my car about 15k miles ago, the problem is that Im starting to get gear noise on decel and I was wondering other than a rebuild is there anything that I can do. It always made noise but its nothing like what it has been and its progressively getting worse.

November 16th, 2011, 01:09 AM	#3
bulloch27 Hardcore Enthusiast 2003 Mustang Fauxbra N/T @ Fast Join Date: Jan 2011 Location: Statesboro, Ga Posts: 2,879 iTrader: 0 reviews	That is typically caused by inadequate pinion preload or the pinion nut backing off (which would also be lack of preload). Remove the driveshaft flange and hit the pinion nut with an impact and the noise will most likely vanish. __________________ All the typical bolt-ons, well a lot are welded on. Bone stock I tell ya. First time at the track, what do I do now? 03 Silver Fauxbra; 06 Legend Lime GT, 89 Outwlaw 10.5W Coupe, 93 Teal Cobra, 93 Red GT, 93 Teal LX - All Sold

November 16th, 2011, 02:38 AM	#6
Nitmare67 Hardcore Enthusiast Join Date: Feb 2010 Posts: 1,391 iTrader: 0 reviews	You may get the pinion too tight increasing the pinion bearing preload and burning it up. Change the oil and check the backlash while your in there. Also check for pinion movement. The good thing is 90% of the time you will get noise but no wear. Its just harmonics. __________________ 99 Mustang GT 446rwhp, Vortech Aftercooled, Killer Chiller @12lbs, HPX, 3.73s, MGW, Battery Relocation, Intercooler Tank Relocated, CF DF clutch, Steeda Quick Release Quadrant, 75mm TB, Ported C&L Plenum, Stock PI Cams Advance 4 degrees, Pro Chamber

November 16th, 2011, 10:13 PM	#8
gdl Regular 99 Cobra, 03 Mach1, 07 CS Join Date: Oct 2008 Location: Grapevine, TX Posts: 373 iTrader: 0 reviews	You measure backlash by holding the pinion gear still and then use a dial indicator to measure how much the ring gear moves when you rock it back and forth. Bulloch's right though, noise on decel is a sign of inadequate preload on the pinion bearing. I'd do what he says but maybe sneak up on it, hit it with the impact for just a few seconds, put it back together, go for a drive and see if it's better. If not, do it again. __________________ 2007 Redfire California Special http://i183.photobucket.com/albums/x...n/2007GTCS.jpg 2003 Dark Shadow Grey Mach 1 http://i183.photobucket.com/albums/x...born/Mach1.jpg 1999 Black Cobra Vert

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November 16th, 2011, 02:36 AM	#5
03sonikblu Regular 2003 GT Join Date: Aug 2010 Location: Orange County, CA Posts: 203 iTrader: 0 reviews	And if I were to hit it with an impact how much should I tighten it?

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