Shane780

Which would be more noticeable on an automatic switching from the factory 3.15s to 3.31s or an aluminum drive shaft ? I know both are small gains.

Having that high ratio first gear might make the swich to 3.31s noticable in first gear ? yes/no ?

scottmach

The driveshaft is a lot of money for something you really won't benefit from. It's a good safety feature for the manual cars when dumping the clutch but for an auto to me is a waste of money. You will definitely notice the 3.31's. Not a lot but some.

bluebeastsrt

I'd do 3.55 Gears with the auto if your going to the expense of a gear change. You can probably buy and pay someone to install the gears for you for the same cost of a drive shaft and you'll get a lot more out of the gears.

Shane780

3.55 Ratio seems a little steep. 4.17 first gear ratio, 3.31 final ratio. Is like a manual with 3.73 rear gears. Ill be ordering my 3.31 gears sometime soon, hopefully have them installed this season.

3.66x3.31= 12.1146
3.66x3.55= 12.993
3.66x3.73= 13.6518
3.66x3.90= 14.274
3.66x4.10= 15.006

4.17x3.15= 13.1355
4.17x3.31= 13.8027
4.17x3.55= 14.8035

scottmach

It is to steep. You made the right decision.

Shane780

gears,install kit, pinion bearing and traction lok kit all ordered. Ill post an update once, installed. Probably at least a month away from install.

bluebeastsrt

Ford puts a 3.73 gear in the manual performance pack for a reason, but whatever.

Shane780

"Ford puts a 3.73 gear in the manual performance pack for a reason, but whatever"

automatic with 3.31s is like a manual with 3.73s in first gear. 3.55s is like 4.10s, too steep in my opinion.

bluebeastsrt

It your money bro. Hope there everything you hope they'll be.

Shane780

Im hoping they will be like the difference between a manual gt with 3.55s and one with 3.73s. The math suggests it should be so at least for first gear.

3.66x3.31= 12.1146
3.66x3.55= 12.993
(3.66x3.73= 13.6518)
3.66x3.90= 14.274
3.66x4.10= 15.006

4.17x3.15= 13.1355
(4.17x3.31= 13.8027)
4.17x3.55= 14.8035