Rear Gears

[clintjackson]

Can someone tell me the pros and cons of switching my current 3.27 gears to 4.10's? 92 5.0 AOD. I drive the car mostly highway cruising but the occasional launch would be nice when called for. I don't street race it and would like to have the best all around ratio. Thanks.

 

[reldla1996]

The 4.10's should enable you to spin tires like there's no tomorrow, but they are a bit extreme for a lot of highway driving. Depending on your highway speed, you'll be in the 3000 rpm neighborhood, and your highway gas mileage will drop by 3-5 mpg. I run a 3.73, and my highway mileage went from 30 (with a 3.08) to 24, while my city mileage stayed the same at 20 (I spend a lot more time in 5th now).

 

[AFB]

With 373's where are your RPM's at 80 miles per hour. Im pretty sure Im running stock gears, Im right at 2000 RPM at 80. Just trying to figure out whats back there without having to open it up. Thanks

 

[No.11]

easy. just jack
up the rear (chock the front) and spin the tire one full rotation. take note of how many times the driveshaft spins. that's your gear ratio.

 

[reldla1996]

With 373's where are your RPM's at 80 miles per hour. Im pretty sure Im running stock gears, Im right at 2000 RPM at 80. Just trying to figure out whats back there without having to open it up. Thanks

I'm still putting my car back together, so I can't take the car for a spin and answer your question directly. Tire size and transmision overdrive ratios also play into the equation. Sounds like you have a 2.73, but No.11 has described above how to measure your ratio without taking anything apart: get both rear tires off the ground, and then spin the tires one revolution while counting how many times the driveshaft turns (having two people makes it easier), which gives you the gear ratio. Safety first....