2.73 to 3.23 speedo gear swap

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08-08-2003, 02:53 PM

TheJoeY88

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Transmission: 700R4

Axle/Gears: 2.73

2.73 to 3.23 speedo gear swap

i just changed the rear end gears in my chicks 89 Formula from an open 2.73 to a posi 3.23
i know i have to change the speedo gears
but on GM parts guy said i only have to change the drive gear in the back of the tranny(casue the driven gears are the same)
anyone know which one i need to get?
any site i can look stuff like this up on?
all i see out there is VERY generic stuff
thanks
Joe

Last edited by TheJoeY88; 08-08-2003 at 03:04 PM.

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08-10-2003, 03:22 PM

RMK

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Car: 87 IROC

Engine: modded LB9

Transmission: Pro Built 700R4

Re: 2.73 to 3.23 speedo gear swap

Lets see if I can sort this one out for you.

For the 2.73 there are 2 combos that I know of:

Drive gear Driven gear

16T blue (8640518) 35T orange (9780628)
17T red (8640517) 37T red (1359271)

I know of 3 for the 3.23 combo. The 2 that use the above drive gears are:

Drive gear Driven gear

16T blue (8640518) 42T green (1362049)
17T red (8640517) 44T dk. grey (9780470)

By finding out what color the drive gear is you can then decide which driven gear is the one you need. The 'T' is the number of teeth the gear has, the color of the gear, then the part number in brackets.

Hope this is of some help.

Robert