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I had a local shop install 4.30s in my Cobra. On the drive home I noticed the differential whining pretty loud, especielly on deceleration when it sounds kinda like my table saw. The shop owner tells me he'll make good on it, but I'm concerned because it wasn't right in the first place and the damn shop is an hour away.

Can someone tell me what needs to be checked? Are 4.30s harder to install than 4.10s? Is it impossible to get 4.30s to be as quiet as 3.27s?
 

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Sorry for the distraction, mark. Just subscribing. Interested to see how people respond.

I think the more revs you turn with the pinion, the harder it is to keep quiet (and smooth). But it shouldn't sound like a table saw! That, to me, is bearings...plain and simple.

Good luck, bud. Let us know how it turns out! I have 4.10's going in as we speak, and it hasn't gone so smoothly so far!

TF
 

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Mark, did the guy check for backlash? He should place some dark grease on the back side (coasting) of a gear tooth and see how it meshes with the pinion gear. It (the grease) should show an even patch on the ring and pinion gear teeth. Then of course, there's the "play" on the pinion shaft/bearing. He shoulda used a tool that will measure the travel, and use shims accordingly. I'm not an expert by any means but I've watched and got in the way of a few installs. :D

Edit: I've had people say my 4.30's are relatively quiet but they're no way as quiet as the 4.10's I had. I'm sure the lower gearing ups the db's.
 

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I just ran into this problem not too long ago when 98Silverstang and I did the overhaul on my clutchpack and carrier bearings. It is most likely your shims on each side of the carrier. They probably have to be replaced with smaller or larger sizes. Mine were like a dog was howling back there untill we found the correct shim sizes. Like posted above, your installer needs to use a dial indicator to check backlash. You want a reading between .008 and .014.

Here is a liink to an install and checking backlash. Go to the carrier bearing install.

http://www.angelfire.com/oh5/cpa5oh/cpa5ohtech001.htm
 

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My 4.10s are as perfectly quiet as my stock 3.27s. But then again, I paid a top notch installer $300 to install them (www.eldperformance.com) in Maryland. They can be perfectly quiet, but the installer needs to know what they are doing!

Jeff
 

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my 4.30's WERE quiet until somehow, my shims got worn to sh*t on the right side and nearly broke in half!!:mad: The only way i could tell it was happening was by me taking a right turn at speed and it would sound like you were running over those grooves on the side of the highway to wake you up at night. I'm sure yours aren't doing that so soon, but it was a thought. I had to get them changed back out and I ******d out and got 3.73's in instead. I need to take up a collection so that i can have the 4.30's put BACK in. Lata...
 

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I have a slight wine from my 4.30's that I can live with.

WHERE DID EVERYONE GET THERE SHIMS? Those things are hard to find. I found them individually, allso in a Dif. Clutch rebild kit. I finaly found some at the chevrolet house. Yep thats right chevrolet! from one of the techs.

So where can you find a set?
 

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i totally dissagree with 8-14 thousands on the back lash
i am no expert but i am an ase certified master auto tech,
i say 4-9 thousands on the backlash, but also more important than the back lash is the pinnion depth(most of the time will be right with new crush sleve) needs to be checked deffenatley , and bearing pre load
also, you need to get those gears out ASAP because after a pattren starts wearing on a gear you might as well forget it, ive seen this many times. at my shop a couple months back, we put new bearings and spider gears ring gear and pinnion in a chevy G-20 full size van, the guy that was working for me did all this work includeing new universal joints in a little under 2 hours,
"usually takes me a half a day to get the pinnion depth exactly where i want at and not to mention back lash" well in the mean time he goes to work somewhere else, 2 weeks later the van comes back with a searouis coast side noise thats getting worse and worse, i try personaly to re shim and set up the whole deal, i get the pinnion depth is right, pre load is good and backlash is on like 3 thousans, so i set it to 7 thousands right were i want, well anyways to make a long story short a month later i end up buying him a ring and pinnion. i set it up myself havent heard from him sence:joy:
 

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2WIZE4GM said:
I have a slight wine from my 4.30's that I can live with.

WHERE DID EVERYONE GET THERE SHIMS? Those things are hard to find. I found them individually, allso in a Dif. Clutch rebild kit. I finaly found some at the chevrolet house. Yep thats right chevrolet! from one of the techs.

So where can you find a set?
Ford sells cast iron shims individually, or you can get a pack of stacking shims from www.drivetraindirect.com its like 9-11 bucks and does both sides.

James
 

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My 4.30's are just as quiet as the 3.27s, except
for a very faint whine between 55 & 60, but
you have to be listening for it. The pinion
depth was set with a gauge, and the backlash
was 0.0095". Bearings were reused. Sometimes
the pinion bearing doesn't survive being pressed
off the old and onto the new.

The tires make more noise than the gears.

Sorry it didn't work out for you.
 
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