red99droptop

I am not sure if the previous owner of my car had a gear installed or not. My buddy and I beleive it does have a gear because it pulls so much harder off the line than his does. What is the best way to find out and if I take off the rear diff cover how will I be able to tell what gear ratio it is.
Thanks

yelw02GT

line up next to eachother on the highway and see if your speedos read the same, if yours is off then it has gears..unless he had a programer and adjusted it, in which case your car might even have a mild tune

willyd465

gear calculator

http://www.tchracing.com/tech/gearcalc.php?tirenum1=245&tirenum2=45&tire num3=17&diameter=&finalgear=3.90&trans mission=tr3650&operation=rpm&givenval=80&a mp;givenvaltype=MPH&selectedgear=5

jmk3

Put it on jack stands & mark the inside bottom edge of tire with chalk, then mark driveshaft with chalk. Turn shaft & count # of revolutions it takes to make tire go round 1 time. A little more than 4 should be 4.10's, 3 & 3/4 turns is 3.73's, 3.5 turns is 3.55's. Do it 2 times to be sure & you should know. Opening up the diff cover probably won't help unless you remove the axles & carier to see end of pinion gear.

red99droptop

Thanks for the responses. I will try all the ideas and see what I come up with.

8banger

If you decide to open the cover,,,count the teeth on the crown gear and the pinion,devidethe crown teeth by the pinion and walla.....or most crown gears are maked 41-10=4.10 or 41-11=3.73.......or you can count the rotations of the wheel vs the shaft as described.

red99droptop

I just drove down the highway and was running 2500 rpm at 85mph so I figure I have 3.27 gears, thats what they come with factory correct.
Thanks