how to know??

[ali pontiac]

hi all
i just want to know if my1999 Z28 M6 have 3.73 gears, the original owner said he installed the gears,is there anyway to know if it its 3.73 or stock gears??

[pajeff02]

Block the front wheels and put the rear up on jackstands. Place the transmission in neutral. Get under the car and make a mark on the inside of your tire and on your driveshaft or pinion. Rotate the driveshaft and count how many revolutions it takes to make the tire go around once. You should end up real close to 3-3/4 turns of the driveshaft if you have 3.73 gears.

[Smittro]

...and to add, 3.73 = 3 turns on the pinion to .73 or nearly 3/4 of one full turn on the ring if I remember correctly..

[0rion]

there are mph/rpm/gear conversion charts out there. This is the only one I could find with a quick search but there are better charts out there. This one uses a 1:1 drive so put your car in 4th and pick a mph and look at your rpm then plug it in and it should tell you your gear ratio.

About 3/4's of the way down the page.
conversion charts

[redbird555]

Or a very definitive way to know is to just take the pan off the rear and on the pinion there will be two numbers divide them out and see if they come to 3.73. Of course this means ull need to change the oil.