When I did the lift on my truck years ago, I was asked the tire size I wanted which is 31's. The tech said 4:10 is the ratio that suits 31's just fine. Since I have the 3.0 & the 4:10 my truck has never had anykind of power issue since day 1. No drop in gas, get up & go, or driveability besides 4:56 was more expensive so I settled for the 4:10. Over the years even on TRS & RPS 4:56 was a better gear if you are running 33's or bigger.
Since I have been using the 4:10 on my 3.0 2wd ranger for around nine years now, I will go ahead & put 4:10's in my other ranger. That is a good setup for me, & it does real good at least for me anyway. My 3.0 is not weak with those 4:10's since it has the 5spd. It can & will get out of it's own way.
Why do you think 4:56 would be better on the 3.0 than the 4:10?
Where did you find that 4:10 gear is wrong for the 3.0?
Was this tech familiar with the 3.0 engine when he told you that?
The 3.0L torque peaks at a much higher RPM than many engines (3250-3750 depending on year). If it cannot spin enough RPM, not only will the power be less, so will MPG.
Nowhere did I say 4.10 is a "wrong" gear either, it's just not as ideal as 4.56 would be.
If you've been happy with 4.10 and are determined to stick to them, then that's certainly fine (it's not hugely different than 4.56). It's going to feel quite a bit different on a 4x4 than a 2WD though (I regretted my choice of 4.10s on my 4.0L 4x4, which I loosely based on the experience I had with a similar 2WD truck).
Anyway, I'm only here trying to help. Good luck on it
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