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3.90 Update


knkayotte

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Well, I got them installed, and their noisy as heck. I love the performance, but the whiny gears are driving me nuts! :angry

Cruising at 55+ is not bad, until you let off the throttle, you can hear it whine indicating bad pinion setup. It also whines constantly between 20 and 50, in town kinda of driving.

Will call IKERD's and see what kind of run around there going to give me.

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Will call IKERD's and see what kind of run around there going to give me.

good luck. from my reading that whine is a sign of a bad break in OR very bad setup. an honerable shop can crack it open and tell how the abuse came to be.

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Will call IKERD's and see what kind of run around there going to give me.

good luck. from my reading that whine is a sign of a bad break in OR very bad setup. an honerable shop can crack it open and tell how the abuse came to be.

It was noisy right from the get go. I'm thinking bad setup, I knew it had issues before making it out of my street, just didn't sound right. Backlash was .01 when I checked it before install which is a little much imho. Should be .006 to .008. Pattern on the marking compond (which was still on the gears from IKERD's) looked good so I wasn't concerned.

Installed a drain plug as well, I'm sure there going to give me heck for that.

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Will call IKERD's and see what kind of run around there going to give me.

good luck. from my reading that whine is a sign of a bad break in OR very bad setup. an honerable shop can crack it open and tell how the abuse came to be.

It was noisy right from the get go. I'm thinking bad setup, I knew it had issues before making it out of my street, just didn't sound right. Backlash was .01 when I checked it before install which is a little much imho. Should be .006 to .008. Pattern on the marking compond (which was still on the gears from IKERD's) looked good so I wasn't concerned.

Installed a drain plug as well, I'm sure there going to give me heck for that.

in my opnion YOU should be giving them backlash. Hassle for shipping, down time, warrnty work, on an item that should have been done right the first time.

If you measured a .01 of the unit form the shop that is bad. Its off by a Factor of 10.

damm....

good luck bud

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Sounds like when I had my 3:90's installed on my 98 SS Camaro by a shop in South Scottsdale. They lasted about 9,000 miles before blowing up. It got louder and louder as the miles went by.

I would honestly say that there are literally only a handfull of mechanics in the country that can set up a rear end properly that would last.

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I installed a set of Richmond 3.91's in my old 340 Dart. Even with a by the book setup , perfect backlash and a good mesh pattern they were still made a little noise on a coast. In my experience some gears just make noise. However if people are diving for cover when your driving by (if they are that loud) then their is a problem.

I have installed several sets of gears (my dart , and a few sets in 5.0's ) however i'm not going to attempt a setup in my 92 vette , I think im going to go the easy way and buy the differential all setup and ready to go =D

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Some whine, some dont.

-shrug- ... our brand new Durango right off the showroom floor with 3.91's whined.

Not much, and we traded it for our Vette about 100k and 6+ years later.

The 4.89's in my old Duster whined purty good on decel.. ran them hard in bracket racin (to the tune of twistin th axles a little even)

..sold them with the car after they had been in for 8+ years of bracket fun :)

The 3.90's whined a bit :) ..pumpkin was setup by the same guy in SoCal long ago ..Dodge 8 3/4 rear was nice to work with, 30 minute gear change by swappin the pumpkin ..is why the 9" ford rear is popular, same deal, just swap out the pumpkin for gear changes :)

-Frank

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Some whine, some dont.

-shrug- ... our brand new Durango right off the showroom floor with 3.91's whined.

Not much, and we traded it for our Vette about 100k and 6+ years later.

The 4.89's in my old Duster whined purty good on decel.. ran them hard in bracket racin (to the tune of twistin th axles a little even)

..sold them with the car after they had been in for 8+ years of bracket fun :)

The 3.90's whined a bit :) ..pumpkin was setup by the same guy in SoCal long ago ..Dodge 8 3/4 rear was nice to work with, 30 minute gear change by swappin the pumpkin ..is why the 9" ford rear is popular, same deal, just swap out the pumpkin for gear changes :)

-Frank

I could deal with a bit of whine, I've taken the vette out a few time to see if I could live with it, but it's pretty bad and getting worse. On my last break-in run, it whined constantly.

Maybe I should just do a solid axle conversion with a ford 9", almost as cheap as rebuilding the whole dang rear end. Autofab has a nice kit.

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These guys are a class act, their going to replace the 3.90 gears with 4.10's no questions asked. Are even paying freight back to their shop. :partydance:

They claim 3.90's have always been a problem and are pulling it from their catalog.

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