my rear end is making some noise so i figure while i'm getting it redone now is the time if im going to change gears. the stock are 355 and my normal commute has a good bit of elevation change i normally have to drop from 5 to 4 a few times figured i could help it out. plus i'm wanting to lift it and go with 285 75 16 in the near future. just looking for some help right now with 265/70/16 at 70 i'm right at 2k. thanks for any help 4.7 5spd 4x4

 

i have 2001 dak 3.9 auto trans. had a 3.55, i drive ONLY in town. put a 4.1 gear posi. my MPG went from 8-9 to 11-12 MPG. cause it started going into D.O. at 35 MPH. if you drive the high way much do not do a 4.1. iam only using stock tires. after looking at a good gear chart is seams that tire size has less effect than gear ratio.

 

Go with at least 4.10 gears. Having a 4.7 with 285/70/17s my truck downshifts on any hill. I even have HO cams, too.

 

4.10 and dont look back.

 

yes 4.10 are the way to go,

 

I got to say 4.10, they are amazing, the only engines I would say you can go lower with (392, 373, 355) are the 5.2 and 5.9 because of more torque down low, but even those engines benefit from better gearing like 410, steep hills less downshifting, better in town mpg. And best of all, no matter what engine you have, with 410 you will notice a performance improvement for acceleration.

 

I wish they made 4.30's for the chrysler axles. That would be the perfect cross-over between the ten and fifty-six.

 

I can say if you do any driving over 60mph dont do 4.10's. I had them in my truck with 33's and it was 2,000 rpms at 60. Id go no more than 3.92 if you do but also remember that the front diff has to get changed too. Looking at about 1,500-1,800 to have a good shop get it completely set up. Unless you have bigger tires I wouldnt worry about it. You have a 5 speed so its pretty easy to have the right rpms. Add a little bit more power like intake,exhaust,tuner and throttle body and you will notice a big difference.

 

What would you gain by changing the gears with a manual transmission? You would be starting out in 2nd gear instead of 1st if you made a drastic change.