Hey. I got into my head that I should go to a lower gear ratio in order to get a better MPG since I am doing a lot of highway driving this year.

I have no problem finding the 2.71 option for the Chrysler 8.25, but I can't seem to source it for the Dana 30. Could you point me to a website or two? Thanks.

 

1) It would be a dog for acceleration
2) The typical 4x4 gear swap will run you $1500 minimum in parts & labor
3) To break even on that, if you are getting 18 mpg now, and you move up to 22 mpg with the new gears, @ $2.00/gal, you'd have to drive 75,000 miles just to break even


Simpy not worth it.



.

 

The jeep is already geared for economy from the factory. If you put gears in that high you will have to drop out of overdrive more and you will likely get worse fuel economy.

 

For what the gears cost and having a shop do it,Or can buy a cheap beater import that will get double the mileage of your jeep.Drive that and have your jeep as a weekend play toy youll save more money this way.And like said anything lower then stock gearing will never hit over drive and end up sucking down more gas.

 

2nd this

 

If your XJ has stock gearing for a 4.0, auto trans the 3.55's are the best you can do for on or off road as far as MPG goes.

You need to look in other places to improve the mpg like a full tune-up using all new parts, guessing being you did give any details on your XJ. you do need the stock tire size for mileage shown to get a real read on everything.

 

Thanks for the input, I have already considered most of these. However, could someone actually answer my question? Where do I find the 2.71 ring and pinion for a Dana 30?

 

If you can't find it, chances are they don't make it.

If you want stellar milage, this probably isn't the ride for you.

 

The short answer is no one makes them,Factory the lowest dana 30 gear is the 3.07 the sticks used,Most jeeps and even the early broncos a 3.55 was its lowest gear.And only time i seen a gear as low as a 2.71 was some of the 60s 6 cylinder cars before the over drive trans.Which is why you can find it for the chrysler rear end that was used in some cars long time ago.

 

Regearing like that is insane. The extra throttle opening to get the dog moving and maintaining speed will more than negate any hopeful gains.

IT WILL NOT WORK!!!!!!

 

No such beast for the Dana 30. As stated the 3.07 is the tallest gear made for the 30.

MAx

 

An FYI:

Years ago I swapped from 2.35 gears in an AMC eagle wagon to 3.54 gears. My gas mileage improved......

 

you would probably get better millage going to deeper gears what for not having to push the gas as hard to get it moving. probably only applicable in town though