I checked the gearing on my car the other day by going to 70 in 4th gear (the 1:1) and it was at 3200 RPM instead of 3400-3500. I'm assuming that means that a previous owner of my car had replaced the stock gearing with a 3.23. Another thing that leads me to this scenario is that I got a ticket yesturday for going 17 over the speed limit when I was actually only going about 10 over. And I've recieved two warning for speeding alreaddy when I feel that I've been going within reason over the speed limit 5 - 10 over....

So...how can I check for sure if its 3.23s or 3.46s?

...and how can I recalibrate the speedo for the correct gearing?

 

3.46 geez dont think i ever heard of those for f-body rear ends 3.23 pretty common,now to oficially find out you would have to take of the differential housing cover off and count the teeth on the ring and the pinion.You need to divide the ring teeth by the pinion teeth= your gear ratio .Now if he changed tire/rim size that can also mess with the mph readin you will need to find that out too,after you get those specs you can easliy reprogram that into your cars comp with a hypertech powerprogrammer.hope that helps with your mph readings.

 

I just had my g/f drive next to me on a 2 lane road and while she was doing 45 my car was doing between 39 and 40....

I'm pretty sure manuals came stock with 3.46s

How much would it cost to have a dealership recalibrate it? I'm taking it in tomarrow anyway to get the EGR valve fixed.

 

no go on the 3.46's

maybe they are different sized tires? thats not much differance. maybe you have 3.73's but larger tires

 

All m6 cars came with 3.46 gears. Automatics come stock with 2.73 with 3.23 available as an option. If your tire height is greater than 26 in it will also cause your speedo to read slow but it would have to be a pretty big jump in size to get that kind of reading. Have you changed your gauge face? Maybe the needle was put on wrong and it is reading incorrectly because of that.

 

and how do you know this?

they ARE 3.42's stock..... trust me, i have an M6

 

3.46 im sorry but ive never seen or even heard of a 3.46.someones got to be pullin you leg on that gear ratio

 

I did a search and thats what came up all the time when people were talking about manual transmissions.

Will the Hypertech programmer be able to figure out a code that my car is throwing at me? My Service Engine Soon light comes on and I'm PRETTY sure its the EGR valve. I'm paying $77 tomarrow just to have a dealership look at it. If the Hypertech would be able to recalibrate my speedo and find the code, it would have paid itself off alreaddy I think.

 

the only gear ratios stock that came in f-body's were 2.73,3.23,and3.42 that was the highest they came.as for the aftermarket gears never even heard of 3.46 on the f-body's.

 

3.42 3.46 same difference its alot closer than 3.23

 

hypertech wont find the code for the "service engine soon" light

 

Holy crap, just found out I can go down to Auto Zone and get the SES light checked out for free. Just saved $77

Does anyone know how to recalibrate the speedo or know how much it will cost to have it done?

 

Buy a used Hypertech off ebay or go find someone with LS1 edit. Usually shops that offer tuning will do simple things like remove EGR, cal. speedos, eliminate skip shift, etc. for about $100 or so. So, check around.

 

i am interested in this issue of tire/wheel size and gear ratio...how or what can one do to use this as a reason for speeding without getting burned too bad for speeding when one gets cited? also, i have never heard of 3.46 gears in a fbody. i know this: my 97 z28 has 2.73 gears, my 96 has 3.23 and i think my 02 ss has either 3.23 or 3.42 not sure. i know the way to check is to see if the rpo code is gu2, gu3, gu4, gu5, gu6.

 

not the same

just don't want ppl getting false information. i've had false information given to me and its made me look like a fool. don't want other ppl doing the same so no hard feelings