change from 259 to a 354 diff.
Thread Starter
2nd Gear
Joined: Mar 2002
Posts: 2
Likes: 0
From: Greer SC
change from 259 to a 354 diff.
I have a 1994 LT1 corvette and have change the diff. from a 259 to a 354. In addition to reprogramming the computer do I also have to change the (reluckter ring)(sp.) in order for the car and the speedometer to perform correctly
Burning Brakes
Joined: Apr 1999
Posts: 754
Likes: 0
From: Lehighton PA
Re: change from 259 to a 354 diff. (ezmask)
yes the speedo gear on the trans tailshaft has to be replaced,a few members done this deal and could chime in on the correct gear.good luck and bye the way how is the performance with the new gears?greg84
Melting Slicks
Joined: Sep 2000
Posts: 2,710
Likes: 1
From: Green Bay WI
Re: change from 259 to a 354 diff. (ezmask)
I have a 1994 LT1 corvette and have change the diff. from a 259 to a 354. In addition to reprogramming the computer do I also have to change the (reluckter ring)(sp.) in order for the car and the speedometer to perform correctly
(1) Gear (GM #25513050)
(1) Gear (GM #8642620)
(1) Seal (GM #1358899)
I'm not sure if your '94 needs all of these parts, so be sure to check before you order. Hope this helps! :)
Le Mans Master
Joined: Feb 2001
Posts: 6,022
Likes: 37
From: SW Fla
Re: change from 259 to a 354 diff. (cprgmr)
When I went from 2.59 to 3.73 I reprogrammed and adjusted tire hieght to get the speedo right. I used the HPP to do that.
[Modified by JPLT1, 8:24 PM 3/26/2002]
[Modified by JPLT1, 8:24 PM 3/26/2002]
Le Mans Master
Joined: Aug 2001
Posts: 5,626
Likes: 1
From: Cinti,OH 2004 Z06
CI 4-5-6-7-8-9-10 Veteran
St. Jude Donor '07-'09
Re: change from 259 to a 354 diff. (ezmask)
My new gears came in today. I am upgrading from 2.59 to 3.31's.
I have a 1995 w/auto tranny. I am running the stock tire size in the rear.
What do I need to do to correct my speedometer. I do have the hypertech
III, but the 3;31's are not listed...Thanks in advance :confused:
I have a 1995 w/auto tranny. I am running the stock tire size in the rear.
What do I need to do to correct my speedometer. I do have the hypertech
III, but the 3;31's are not listed...Thanks in advance :confused:
Team Owner
Joined: Sep 2001
Posts: 62,160
Likes: 1,733
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Re: change from 259 to a 354 diff. (Vette Ed)
My new gears came in today. I am upgrading from 2.59 to 3.31's.
I have a 1995 w/auto tranny. I am running the stock tire size in the rear.
What do I need to do to correct my speedometer. I do have the hypertech
III, but the 3;31's are not listed...Thanks in advance :confused:
I have a 1995 w/auto tranny. I am running the stock tire size in the rear.
What do I need to do to correct my speedometer. I do have the hypertech
III, but the 3;31's are not listed...Thanks in advance :confused:
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Team Owner
Joined: Sep 2001
Posts: 62,160
Likes: 1,733
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Re: change from 259 to a 354 diff. (Half Fast)
oh and for a 94 youll just need the hypertech or a custom flash
Advanced
Joined: Mar 2002
Posts: 96
Likes: 0
From: Columbus Ohio
Re: change from 259 to a 354 diff. (cprgmr)
I was wondering if you checked into the speedo calibrator that Zip products has out for the 93's. I am in the process of doing the same gearing change and I was told that this calibrator was much more accurate but it cost me around $160.
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
Re: change from 259 to a 354 diff. (ezmask)
I have a 1994 LT1 corvette and have change the diff. from a 259 to a 354. In addition to reprogramming the computer do I also have to change the (reluckter ring)(sp.) in order for the car and the speedometer to perform correctly
Melting Slicks
Joined: Sep 2000
Posts: 2,710
Likes: 1
From: Green Bay WI
Re: change from 259 to a 354 diff. (Red 86 4+3)
93 and earlier use gears and a sensor.
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
Re: change from 259 to a 354 diff. (cprgmr)
93 and earlier use gears and a sensor.
What sensor is this? I contacted 18carfan (who I ordered from) and he told me that I only needed two gears and the rear tranny tail seal. :confused:
What sensor is this? I contacted 18carfan (who I ordered from) and he told me that I only needed two gears and the rear tranny tail seal. :confused:
Le Mans Master
Joined: Oct 2000
Posts: 6,362
Likes: 30
From: Oak Harbor WA
Re: change from 259 to a 354 diff. (Red 86 4+3)
93 and earlier use gears and a sensor.
What sensor is this? I contacted 18carfan (who I ordered from) and he told me that I only needed two gears and the rear tranny tail seal. :confused:
Thats strange. 18 carfan is who sold me mine. When you change the 2 gears, the spacing between them no longer aligns with the old sensor. So a new sensor has to be used which has a different spacing. Now the sensor I am referring to is the one that the driven gear goes in and the wiring plugs into it.
What sensor is this? I contacted 18carfan (who I ordered from) and he told me that I only needed two gears and the rear tranny tail seal. :confused:
Thats strange. 18 carfan is who sold me mine. When you change the 2 gears, the spacing between them no longer aligns with the old sensor. So a new sensor has to be used which has a different spacing. Now the sensor I am referring to is the one that the driven gear goes in and the wiring plugs into it.
Team Owner
Joined: Nov 1999
Posts: 26,679
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From: This vette goes to 11 Milford MA
St. Jude Donor '03-'05
Re: change from 259 to a 354 diff. (Goody)
I just did this last night and went form 2.59's to 3.07's in my 88. I ordered my parts from 18carfan also. I got the VSS and a green gear. It wouldn't fit the old VSS because you are using a bigger gear so the shaft in the VSS has to be offset to compensate. Unfortunately, the one I got didn't work either untill I spun it 180* to put the offset where it needs to be. I don't know if I was sent the wrong part or if I am just lucky and got a defective one but it caused me a giant MF'ng headache untill I figured it out.
Safety Car
Joined: Dec 1999
Posts: 4,691
Likes: 1
From: Framingham MA
Re: change from 259 to a 354 diff. (cprgmr)
93 and earlier use gears and a sensor.
What sensor is this? I contacted 18carfan (who I ordered from) and he told me that I only needed two gears and the rear tranny tail seal. :confused:
What sensor is this? I contacted 18carfan (who I ordered from) and he told me that I only needed two gears and the rear tranny tail seal. :confused:
Burning Brakes
Joined: Aug 2000
Posts: 1,052
Likes: 0
From: Warrenville IL
Re: change from 259 to a 354 diff. (Vette Ed)
My new gears came in today. I am upgrading from 2.59 to 3.31's.
I have a 1995 w/auto tranny. I am running the stock tire size in the rear.
What do I need to do to correct my speedometer. I do have the hypertech
III, but the 3;31's are not listed...Thanks in advance :confused:
I have a 1995 w/auto tranny. I am running the stock tire size in the rear.
What do I need to do to correct my speedometer. I do have the hypertech
III, but the 3;31's are not listed...Thanks in advance :confused:
For the 94, I found that the 3.45 gear ratio in the programmer worked best with the 3.54 gear.