Gear installation question
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Joined: Aug 2004
Posts: 89
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Gear installation question
I just had a local shop put 3.42 gears into my automatic 98 C5 which previously had 2.73's. Got the car last night and have a couple of questions:
First, the shop is trying to use a hypertech to help me change the gear ratio. They were unable to get it to work yesterday. I have read on here that this will not work with non factory gear ratios, and the 3.42s are just that in an automatic. If this is in fact the case, what other option do you recommend to reprogram the computer. This is my daily driver and I would prefer something where I do not have to mail in my computer.
Secondly, I have noticed a little fluid leaking from the rear on to my driveway after the install. This happened last night after I got it, and a little this morning after I drove around some. Is this normal after a gear change? What would be causing this?
Car definitely runs quicker, however I'm afraid to really get on it until I get the shifts reprogrammed.
Thanks for your help.
Josh
First, the shop is trying to use a hypertech to help me change the gear ratio. They were unable to get it to work yesterday. I have read on here that this will not work with non factory gear ratios, and the 3.42s are just that in an automatic. If this is in fact the case, what other option do you recommend to reprogram the computer. This is my daily driver and I would prefer something where I do not have to mail in my computer.
Secondly, I have noticed a little fluid leaking from the rear on to my driveway after the install. This happened last night after I got it, and a little this morning after I drove around some. Is this normal after a gear change? What would be causing this?
Car definitely runs quicker, however I'm afraid to really get on it until I get the shifts reprogrammed.
Thanks for your help.
Josh
Melting Slicks
Joined: Mar 2005
Posts: 3,222
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From: Mayfield kentucky
Hi Josh, A hypertech programer will only work with stock gear ratio and this would be 2.73, 3.15, and 3.42 so the hypertech will work. Now if you ever had your computer tune by a tuner like Breatless, DTE, LG Motorsports a hypertech programer will not work for it does not see stock cal numbers. Now as for your leak it might be a little that got split on the frame give it a day or two if it still leaks then go back. You can send your computer to DTE in Fort Wanye, In. and they will program it for $50.00 Good luck 
Melting Slicks
Joined: Feb 2004
Posts: 3,137
Likes: 1
From: Insane Diego Kalifonya Baby
Originally Posted by vettes4fun
Hi Josh, A hypertech programer will only work with stock gear ratio and this would be 2.73, 3.15, and 3.42 so the hypertech will work. Now if you ever had your computer tune by a tuner like Breatless, DTE, LG Motorsports a hypertech programer will not work for it does not see stock cal numbers. Now as for your leak it might be a little that got split on the frame give it a day or two if it still leaks then go back. You can send your computer to DTE in Fort Wanye, In. and they will program it for $50.00 Good luck
Le Mans Master
Joined: Jul 2002
Posts: 7,370
Likes: 8
From: Slave to the evil empire
Cruise-In V Veteran
St. Jude Donor '04
If the diff was overserviced then it will leak a little out the vent, if it continues to leak after 3 or 4 days of daily driving then I'd be concerned.
Safety Car
Joined: Aug 2000
Posts: 4,154
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From: Murphy TX
Cruise-In II Veteran
The HPP3 isn't going to do what you need. My own programming preferences are Carputing's LS1-Edit and EFI Live's FlashScan. FlashScan is the better investment but it won't help at the moment with your 98. If you opted for the mail order route instead, you might look into getting the replacement PCM shipped to you to minimize downtime. The kink is that 98 PCMs are a little more scarce.
Can you identify where the leak is coming from? Is it anywhere other then the blow off tube?
Can you identify where the leak is coming from? Is it anywhere other then the blow off tube?
Racer
Joined: Jan 2005
Posts: 311
Likes: 1
From: Arkansas
I have a Predator programmer, which only asks you what was the stock ratio before you changed your gears. Then it allows you to select the gear you have installed so the speedo reads right.
Mine came with a custom tune from SLP. But it still allowed editing of that tune. I say get a Predator.
When I had my 3.42 installed, the mechanic missed tightening a bolt on the very top of the carrier. It leaked like crazy. Took two returns to find the problem.
It could just be fluid spilt in the chassis, but after one or two days, I'd get concerned.
Mine came with a custom tune from SLP. But it still allowed editing of that tune. I say get a Predator.
When I had my 3.42 installed, the mechanic missed tightening a bolt on the very top of the carrier. It leaked like crazy. Took two returns to find the problem.
It could just be fluid spilt in the chassis, but after one or two days, I'd get concerned.
Drifting
Joined: May 2003
Posts: 1,715
Likes: 1
From: cAshburn VA
Drive it around today, when you park it tonight check/wipe the rear down. If you still have a leak in the morning, take it back, they didn't seal it right. First time I had the dealership fix the tranny it took them three tries to get the rear sealed up right. Don't fall for that, "some sepage is normal" scheisse. On my second rear, second tranny, third clutch(soon to be 4th), and as many times as my rear has been off, when it is done right, it don't leak.
I had a hypertech years ago, and I remember only seeing 2.73 and 3.15 as an option, but I was just breezing past that anyway, hmm...
Not an expert, just my $.02... Good Luck!
I had a hypertech years ago, and I remember only seeing 2.73 and 3.15 as an option, but I was just breezing past that anyway, hmm...
Not an expert, just my $.02... Good Luck!
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Joined: Apr 2001
Posts: 54,204
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From: S.W. Ohio. . . . . . NRA Life Member
for the record, the HPIII will not gear scale the C5 A4... period - end of story; if you go beyond the 3.15 ratio. It goes through all the motions - then you end up popping the P1870 error code after a few hundred miles of driving.
If you don't believe me; then call Hypertech themselves. They'll tell you the same, and then have no sympathy that their advertising is false.
It works great on F-Bodies; but they failed to incorporate the uniqueness of the C5 into their programming.
----------------------
Now about the Predator.
There are three models of Predator that will work on the C5:
1. 1999 thru 2003 exclusive model.
has a gear-scale bug that it too won't properly scale beyond
the 3.42
Good news is that it can be modified via a custom tune to correct
the problem. This specific "custom tune" should be provided free
from Diablosport or the dealer you purchased from.
2. 2003 only model.
does not have the gear scale problem, and introduces more fields
of adjustment on various screens
3. 2004 only model.
does not have the gear scale problem, and has the same extra adjustment fields as the 2003 only model.
.
If you don't believe me; then call Hypertech themselves. They'll tell you the same, and then have no sympathy that their advertising is false.
It works great on F-Bodies; but they failed to incorporate the uniqueness of the C5 into their programming.
----------------------
Now about the Predator.
There are three models of Predator that will work on the C5:
1. 1999 thru 2003 exclusive model.
has a gear-scale bug that it too won't properly scale beyond
the 3.42
Good news is that it can be modified via a custom tune to correct
the problem. This specific "custom tune" should be provided free
from Diablosport or the dealer you purchased from.
2. 2003 only model.
does not have the gear scale problem, and introduces more fields
of adjustment on various screens
3. 2004 only model.
does not have the gear scale problem, and has the same extra adjustment fields as the 2003 only model.
.
Last edited by Mike Mercury; Jul 17, 2005 at 10:54 AM.