GT23

I'm just wondering for the last two years with the inline 6, there is two types of transmissions, the 4 speed and 5 speed, wondering if there is a huge diffference between the two between smoothness, acceleration, gas mileage?

Anyone happen to know the gear ratios for each gear of both of the transmissions?

lexrex

The 5 speed should get better gas mileage and be less "buzzy" at freeway speeds. I don't know the gear ratios off the top of my head, but the 4th gear in both transmissions is a 1:1 direct drive. The 5 speed adds an overdrive that is around 0.83:1 or 0.75:1. The 5 speed is a lot smoother, but supposedly more troublesome.

In practical terms, the 4 speed hits 3,000 RPM in top gear at about 70 MPH, whereas the 5 speed doesn't cross 3,000 RPM until about 85 MPH. The 4 speed will have better freeway acceleration in top gear since the revs are higher. But if you manually shift the 5 speed down into 4th, they're identical.

Personally, I'd take the 5 speed.

lexrex

Found the gear ratios for the 5 speed:

MB AMG

Can someone please describe the gear ratio numbers to me? Is it every wheel rotation to engine RPM?

zam2000

Take example, 3rd gear: 1.41

It means the input shaft (before enterring the tranmission) have to turn 1.41 round for the output shaft (end of tranmission) to turn one round.

So yes, they're related to engine RPM. Knowing gear ratio and differential ratio, along with wheel diameter, you can calculate speed in related to engine RPM.

lexrex

"How Gear Ratios Work"

MB AMG

Thanks very much!