Axle ratio question
Hotshot
Joined: Nov 2000
Posts: 11,591
Likes: 14
From: Pflugerville, tx
so the lower number ratio contributes to better mileage.
Sam
Postmaster
Joined: Aug 2006
Posts: 2,829
Likes: 3
As pointed out the 6R140 transmission is geared differently which also changed the axle ratio offerings making 3.73's unnecessary with the 6.7L.
Here are the final drive ratio calculations based on a 5R110W w/ 3.73's.
1st Gear - 11.60
2nd Gear - 8.28
3rd Gear - 5.78
4th Gear - 3.73
5th Gear - 2.65
Reverse - 10.74
Now here are the final drive ratio calculations based on the new 6R140 w/ 3.55's.
1st Gear - 14.11
2nd Gear - 8.23
3rd Gear - 5.38
4th Gear - 4.08
5th Gear - 3.05
6th Gear - 2.39
Reverse - 11.10
As you can see the 6R140 w/ 3.55's actually has a much deeper 1st gear once everything is calculated out. The 5R110W in this case would need somewhere between a 4.30 and a 4.88 axle ratio to equal the 1st gear pulling power of the 6R140 w/ 3.55's. Mind you that none of this takes in account for the additional power of the 6.7L.
Here are the final drive ratio calculations based on a 5R110W w/ 3.73's.
1st Gear - 11.60
2nd Gear - 8.28
3rd Gear - 5.78
4th Gear - 3.73
5th Gear - 2.65
Reverse - 10.74
Now here are the final drive ratio calculations based on the new 6R140 w/ 3.55's.
1st Gear - 14.11
2nd Gear - 8.23
3rd Gear - 5.38
4th Gear - 4.08
5th Gear - 3.05
6th Gear - 2.39
Reverse - 11.10
As you can see the 6R140 w/ 3.55's actually has a much deeper 1st gear once everything is calculated out. The 5R110W in this case would need somewhere between a 4.30 and a 4.88 axle ratio to equal the 1st gear pulling power of the 6R140 w/ 3.55's. Mind you that none of this takes in account for the additional power of the 6.7L.
