getting rid of the crappy 2.73 and going to 3.23

need to know what speed gears to go with, and how to swap them out. for some reason it seems to take an act of congress to get anyone around to even do it, they like use an aftermarket tuner.....ITS NOT A NEW COMPUTER CONTROLED P.O.S.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! oh well you are going to have to take that to the dealer

i know its been talked about on here but i cant get the exact anwsers im looking for in my search

 

also is there anyway to replace just the driven gear and not the drive gear

tire size is 245/60/15

i should have a red driven now, and a red drive....... would a light blue driven work close enough with the red drive

 

bump

 

do a search on yahoo for speedometer world you wil fine what you need there

 

of the rear end gears of the speedo gears? because with the rear end gears you cant do that, since theyre made as a set, and will chew each other up if you use mismatched ones.

 

You need the blue 18 tooth drive gear PN 8640518, and the dark gray 44 tooth driven gear, PN 25513051 for '89-'92 style speedometer, or 9780470 for '82-'88 style speedometer. This'll have you dead-nuts perfectly accurate with 3.23:1 and 245/60R15s

 

ok so we got that figured out, how do i get the drive gear off, i have never done this yet

 

There are any number of ways to break the old gear off, the real trick is to install the new gear without cracking it. Getting it warm will help.

 

I went from a 2.73 to a 3.27 rear end you do not need to change the drive gear. The new gear I got was dark green, but I do not remember if it was off by plus or minus 5 percent of my speed. You will need a new carrier for the driven gear though.

http://www.partshp.com/speedometer_gears.htm

I got my new to me aluminum housing from them. Even though it says they are out of stock on the used ones give them a call and see if they just didn't update there site.

 

You need exactly what I posted. Nothing more, nothing less. I just did this exact thing to my '82 Camaro, with the same size tires as you. It has the 3.23:1 axle from my '84 Trans Am, and a '91 700R-4 running the '82 Speedometer cable. Ignore red lava on this particular one.

 

44/18= 2.444

42/17=2.471

2.471/2.444=1.011

Thats a 1 percent difference between the gear combination that I listed and the one you gave. Save your money and just use 42 tooth

Here is how to replace the driven and the drive gear

https://www.thirdgen.org/speedogear

 

The tranny that I put in my Bird was from a '91 Z28 w/L98 and 3.23 gears. It had the green driven gear but the drive gear was the same red one that was in my original '86 700R4 that came out of my car. The Bird still has the 2.73 open diff. All I did was swap in my 2.73 driven gear into the new tranny and that's it. I'm running 245/50-16's and my speedo is dead accurate. It was dead accurate when I was running the stock 215/65-15's.

 

i usually call local gm dealer if u get someone that knows anything they can help u most of the time l

 

Hello! I have a question for you transmission heads. I used to have a 305 iroc z 1987 and used the 700r4 for a 1981 Malibu wagon. The rear I swapped in is a 2.73posi. as you can imagine the speedometer is off. I was wondering if anyone knows which speed gear combination I need to correct the issue. Up to 40"mph" the km/hr is correct and goes off after that.

 

Part of the issue...we don't know what drive/driven gear combination you have but once you determine that, you should be able to figure out what you need.
https://www.tciauto.com/speedometer-gear-calculator