3.42 Differential question
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3.42 Differential question
A local guy, who lives across the bridge in Arkansas, has a new 3.42 differential for sale that he stated he bought at a Chevy swap meet, thinking that it was a 3.90 because the box was marked as having a 3.90. He said he didn't realize the problem until he had it half-way installed that it was actually a 3.42. 
I guess it could be true.
I'm not a mechanic by any streatch of the imagination and are there any particular things that I should look for when I go to inspect it? I'm sure he won't let me take it anywhere so I have to make the decision while I'm there. Thanks for any help.
I guess it could be true.
I'm not a mechanic by any streatch of the imagination and are there any particular things that I should look for when I go to inspect it? I'm sure he won't let me take it anywhere so I have to make the decision while I'm there. Thanks for any help.
Melting Slicks
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From: Orland Park Illinois
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Getrag puts a metal tag on the upper right corner of the box (as it's mounted on the car). The tag tells you the gear ratio of the box. Ofcourse, we are assuming internal parts haven't been swapped. 
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Originally Posted by BiggieBoy
Ofcourse, we are assuming internal parts haven't been swapped.
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Originally Posted by BiggieBoy
...Ofcourse, we are assuming internal parts haven't been swapped.
since the C5 carrier never came from the factory with 3.90 gears... there was never any tag printed with a 3.90 ratio or 3.90 part number (which there is no 3.90 carrier part number )
And its very popular to take the 3.42 case and install 3.90 ring & pinion gears (and other gear sets) in to it. I guess there's a chance that you have a 3.42 carrier case with 3.90 gears installed in it.
Send it to DTE and have them go-over it.
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He's now telling me that he thought the diff. was a 3.73 when he initially bought it. Did they make a 3.73 for a C5?
Also, if everything check out OK what modifications would I have to do since it is from a Z06?
Someone told me there would be a "drivability "issue, and that it might be a bit more noisier than a diff. designed for a C5 auto.
Also, if everything check out OK what modifications would I have to do since it is from a Z06?
Someone told me there would be a "drivability "issue, and that it might be a bit more noisier than a diff. designed for a C5 auto.
Last edited by Tact; Mar 26, 2006 at 03:35 PM.
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Team Owner
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Originally Posted by Tact
He's now telling me that he thought the diff. was a 3.73 when he initially bought it. Did they make a 3.73 for a C5?
Also, if everything check out OK what modifications would I have to do since it is from a Z06?
Someone told me there would be a "drivability "issue, and that it might be a bit more noisier than a diff. designed for a C5 auto.
Also, if everything check out OK what modifications would I have to do since it is from a Z06?
Someone told me there would be a "drivability "issue, and that it might be a bit more noisier than a diff. designed for a C5 auto.
If it is a Getrag-sold 3.73 carrier, then it would have a different part munber than the one you previously listed.
there's no bolt-up or driveability issues with the Z06 3.42 versus the non Z06 3.42 carrier. The only difference between the two is that the Z06 3.42 has a shot-peened gears (hardened).
Since you have an A4, you will need the PCM reprogramed for your 3.42 upgrade though. What is your current ratio ?
a lot of routine questions answered here:
http://mikemercury.home.att.net/342.htm
.
Last edited by Mike Mercury; Mar 26, 2006 at 07:28 PM.
Collections Hold
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From: Fort Wayne Indiana
Originally Posted by Mike Mercury
there's no bolt-up or driveability issues with the Z06 3.42 versus the non Z06 3.42 carrier. The only difference between the two is that the Z06 3.42 has a shot-peened case (hardened).
Every single other internal and external component of the 2001-2004 Z06 differential is *exactly* the same as any other standard, 3-rib, 3-series differential for any model of C5 Corvette equipped with a 3-series unit. 
DTE
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Originally Posted by DynoTech Engineering
Not the case Mike, just the actual ring & pinion set only. Every single other internal and external component of the 2001-2004 Z06 differential is *exactly* the same as any other standard, 3-rib, 3-series differential for any model of C5 Corvette equipped with a 3-series unit.
DTE
Every single other internal and external component of the 2001-2004 Z06 differential is *exactly* the same as any other standard, 3-rib, 3-series differential for any model of C5 Corvette equipped with a 3-series unit. DTE
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I decided to pass on the rear diff. The seller has it on eBay and only shows a generic picture of a diff. I asked him for actual pictures of the diff. he was selling and I also requested his address so I could come by to inspect it before bidding. He didn't even respond to those requests so I passed. I guess I'm paranoid of people who will do nothing. I'll keep trying to find one here on the forum. Thanks for the help everyone. 
Pro
Joined: Oct 2004
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Originally Posted by Tact
I decided to pass on the rear diff. The seller has it on eBay and only shows a generic picture of a diff. I asked him for actual pictures of the diff. he was selling and I also requested his address so I could come by to inspect it before bidding. He didn't even respond to those requests so I passed. I guess I'm paranoid of people who will do nothing. I'll keep trying to find one here on the forum. Thanks for the help everyone.
Pro
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From: Tampa fl
Buying a used diff is risky business. If the seller or the product seems the least bit "shady" I would run and don't look back. Do yourself a favor and buy one with a warranty from a dealer. This part is very expensive to have installed and if there is a problem with the "mystery diff" then you will be very sorry. 
Melting Slicks
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From: St. Louis Missouri
The rear diff sold on Ebay for $736. I was watching the sale also. You can buy one from Fred Beans for right under $1100.00 brand new and shipped to your door. This might sound high, but consider what I just went through. I bought a used carrier for $500.00 out of a Z06. I had the carrier installed for $350.00 and then had to pay $350.00 to have the carrier switched back to my old one since the Z06 carrier was making noise. Now I have $700.00 invested, since the seller is taking the Z06 rear back and still have my 2.73 gears. I am probably buying new the next time because I don't want to take the same chance.
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Originally Posted by waupachino
The rear diff sold on Ebay for $736. I was watching the sale also. You can buy one from Fred Beans for right under $1100.00 brand new and shipped to your door. This might sound high, but consider what I just went through. I bought a used carrier for $500.00 out of a Z06. I had the carrier installed for $350.00 and then had to pay $350.00 to have the carrier switched back to my old one since the Z06 carrier was making noise. Now I have $700.00 invested, since the seller is taking the Z06 rear back and still have my 2.73 gears. I am probably buying new the next time because I don't want to take the same chance.
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when I upgraded to the 3.42, my 2002 wasn't even a year old (and still under warranty). I wasn't about to risk installimg a used carrier on a Corvette with only 3,000 miles on it.
But, I must say that there are a lot of success stories about buying used carriers here on the forum. But it's always a crap shoot.
But, I must say that there are a lot of success stories about buying used carriers here on the forum. But it's always a crap shoot.
