TIME SENSITIVE! 2.73 to 3.42 Question
Thread Starter
Racer
Joined: Apr 2008
Posts: 408
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From: Santa Clarita CA
TIME SENSITIVE! 2.73 to 3.42 Question
This is no longer time sensitive, but input is still welcome.
I was looking at buying a 3.42 (part #12551769) rear end for my 2000 A4. The seller indicated that this should be used in an M6 due to some old bulletin from GM about gear ratio changes in automatics. I know a LOT of people are running 3.42s in their A4s, is there any truth to what the seller is saying or is it
? Is it specific to that particular part # perhaps? Any issue with A4s throwing an 1870 code after changing to a 3.42, and is this simply resolved by a tune to adjust the shift points?
TIA
I was looking at buying a 3.42 (part #12551769) rear end for my 2000 A4. The seller indicated that this should be used in an M6 due to some old bulletin from GM about gear ratio changes in automatics. I know a LOT of people are running 3.42s in their A4s, is there any truth to what the seller is saying or is it
? Is it specific to that particular part # perhaps? Any issue with A4s throwing an 1870 code after changing to a 3.42, and is this simply resolved by a tune to adjust the shift points?TIA
Last edited by EDenney; May 13, 2008 at 10:35 PM.
Premium Supporting Vendor
Joined: Mar 2001
Posts: 5,241
Likes: 21
From: Knoxville Tennessee
No reason it will not work in your car.
I would recommend having a tuner adjust the shift points.
I make several changes when I do the rear end, even when using a stock trans and converter.
Good Luck
I would recommend having a tuner adjust the shift points.
I make several changes when I do the rear end, even when using a stock trans and converter.
Good Luck
Thread Starter
Racer
Joined: Apr 2008
Posts: 408
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From: Santa Clarita CA
Thanks, that's what I thought. Anyone else? What's a good price for a low mileage used 3.42? $500ish?
Thread Starter
Racer
Joined: Apr 2008
Posts: 408
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From: Santa Clarita CA
Thanks, I saw someone else mention that in another thread. Couldn't see any reason why this wouldn't work but the seller says he's installed like 20 of these and most of them have thrown the aforementioned code in A4s. I had to believe that anyone who's installed so many would know that the shift points need to be adjusted/reprogrammed and the code will go away, so when he said it would only work in a manual I needed some second opinions. Apparently he didn't know this...
Drifting
Joined: Aug 2006
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From: King George Virginia
It will be one of the best mods you will ever do to your car. 3.15s won't cut it not enough change. I love my 3.42s. See my mods, I have already done this. Wait to get the 3.42s you will not regret it.
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Burning Brakes
Joined: Aug 2006
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From: Eastern PA
I think I read a thread in this forum regarding a similar question. But I think if the gears are coming out of a MN6 car the only difference is a piece which has to be switched or moved. I'll try to find the thread and post it.
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From: Simi Valley CA
I did the same swap and coincidentally, on a 2000 coupe A4. Yes, that one will work (agreeing w/ above) and yes, you MUST reprogram for the gear ratio however the shift points are not necessary. If you want to change them, that's up to you. While you're in there, you may want to have them increase the shift pressures. It will give you a firmer shift and a kick in the pants to drive.
ALSO... when you have the swap done, replace the tranny seal. It's a $60 part and is known to leak.. eventually. There's a TSB on it. They start leaking when the car sits in cold weather. Then it increases to just leaking. You don't want to have them pull the carrier twice... like I did.
edit: just thought of one more little tid bit... if you are not having the computer programed at the same place you're having the carrier r/r'd, you can drive it HOWEVER you must drive in 3. NOT OVERDRIVE. If you drive in overdrive, the computer will sense the error in the trans and go into "limp" mode and will then shift with all the grace and delicacy of a sledge hammer.
ALSO... when you have the swap done, replace the tranny seal. It's a $60 part and is known to leak.. eventually. There's a TSB on it. They start leaking when the car sits in cold weather. Then it increases to just leaking. You don't want to have them pull the carrier twice... like I did.
edit: just thought of one more little tid bit... if you are not having the computer programed at the same place you're having the carrier r/r'd, you can drive it HOWEVER you must drive in 3. NOT OVERDRIVE. If you drive in overdrive, the computer will sense the error in the trans and go into "limp" mode and will then shift with all the grace and delicacy of a sledge hammer.
Last edited by Todd157k; May 14, 2008 at 12:09 PM.
Burning Brakes
Joined: Feb 2005
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From: Tulsa OK
I put that rear in my 03 A4 and it has never thrown any codes. Works great and you can really tell the difference. I went from a 3:15 to the 3:42 so if you are starting with a 2:73 you will be reeeaaaalllllyyy happy with the mod. The only programming that was done for the gear change was so the speedo would be accurate.
Do it.
Do it.
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Thread Starter
Racer
Joined: Apr 2008
Posts: 408
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From: Santa Clarita CA
All very helpful information.
I'm slated to have Charlie at RPM tune it as soon as I'm finished with my mods, the last of which would be the rear end, so I'll be in good shape. Just wanted to make sure that I wasn't going to buy a rear end that would throw an 1870 code continuously with or without a tune, as the seller was indicating. He specifically pulled the 3.42 out of an A4 BECAUSE it was throwing the code, and said it should only be put into an M6, so assumably he just didn't know it needed to be reprogrammed (even though he said he's installed about 20 of these!?). As I mentioned, I was outbid on that rear end so I don't have a 3.42 lined up at the moment just yet. If anybody is selling a good used 3.42, preferably with relatively low miles, please let me know ASAP.
I'm slated to have Charlie at RPM tune it as soon as I'm finished with my mods, the last of which would be the rear end, so I'll be in good shape. Just wanted to make sure that I wasn't going to buy a rear end that would throw an 1870 code continuously with or without a tune, as the seller was indicating. He specifically pulled the 3.42 out of an A4 BECAUSE it was throwing the code, and said it should only be put into an M6, so assumably he just didn't know it needed to be reprogrammed (even though he said he's installed about 20 of these!?). As I mentioned, I was outbid on that rear end so I don't have a 3.42 lined up at the moment just yet. If anybody is selling a good used 3.42, preferably with relatively low miles, please let me know ASAP.
Last edited by EDenney; May 14, 2008 at 05:29 PM.