camaro98man

Ok. first off. I know 3.73's did not come stock.

I have a 1999 trans am with an auto trans. When I bought it, mods were already done to it, and the dealer didn't know anything about the mods. So I'm trying to figure out if it has the stock gears (2.73 or 3.23) or if the previous owner changed the gears to 3.73's or something else. Anyone have any ideas on how I can figure it out? Here's a video from 25mph to 70mph, I don't know if it helps at all, but here ya go......

ScreamingEagle

iTrader: (3)

That video doesn't tell much. Was that 2/3 or 1/2 gears? What rpm are you turning at 60? What size tires?

ls1zfast

Put the car on a lift or jack stands. Mark a spot on a rear wheel (12:00), then mark a spot on the driveshaft (12:00). Put the car in N. Count the amount of revolutions it takes the driveshaft to turn the wheels around one time. That is your approx gear ratio. If it takes 3.73 turns of the driveshaft to turn the wheels one revolution, you have 3.73 gears.

DaddySS

2001NBMZ28

You can also try a calculator like www.f-body.org/gears/

JScamaro

iTrader: (6)

Just go cruise at 60 or 70 mph and see what your rpm is at. There is a gear calculator on the boards that shows the mph and rpm for each gear.