time2roll wrote:
Anyone have a 2017 EPA number for 3.15 vs 3.55?
I cannot seem to find much where is ratio is called out.
I doubt there's any real world difference. The 8 / 10 speeds have such tight ratio spread, the rear axle differences becomes almost negligible.
Here's a fund fact, if you look at the chart in the OP, compare a 10 speed 3.15 truck to a 10 spd 3.73 truck, you'll see an interesting pattern: once past 2nd gear, the ratios are almost identical, if the 3.73 truck is in a higher gear!
In a towing situation, if you need 5th in the 3.15 truck, you'd simply pick 6th in the 3.73 truck, and perform nearly identical.
RAM did the same with their 8 spds, a lower gear in the 3.21 truck is nearly identical with a higher gear in the 3.92 truck. When buying, your only decision is - do you value low hwy RPM or super low crawl ratio?
Once you answer that question, gears 3 - 9 makes no difference.
