Yea if you have an auto, and plan on doing some serious offroading, I'd think 513. But if you are DD then I'd say 4.88 is better. I love my Detroit Auto Locker up front. I have a true trac rear. If I didn't go with a true trac I'd have an Eaton E locker or full Detroit locker rear. Lockers are great and if you plan on getting some, then the time to do it is when you regear. And there is a lot of debate on this particular subject. Check the gear chart in the FAQ and follow its advice

 

Newb jumping in for just a second. I feel like the not cool kid listening around the corner and chiming in with nothing to add. Anyways. Just joined the 35 inch club. So i'll ask. what is the cost of changing the gear ratio's? Do you change the front too? Something that needs to be professionally done? Sorry for the hi-jack in the thread.

 

X2. @ 55 with 5:13's I am dead @ 1700 RPM's ... Diesel territory. I mostly cruise with O.D off even with 5:13's @ 60-65 anyhow.

Yes BOTH sets need to be changed. Figure cost for gears and TWO master rebuild sets. Labor really comes into play as to where you live. 4X4 shops in TX for instance have run specials for 99 Bucks an axle (Curse you guys Grrrr) up in the anti-everything New england area expect 500-2K for factory locker equipped rubicons and less for a D30/44combo Truthfully most shops will get between 8-10hrs of labor @ whatever the cost is.

 

2009 Auto w/35's

Just had 5.38's installed. Went to this gear ratio as you never know if 37's are around the corner. This way it will be ready for them. Have only run it a few times but enough distance to put some tanks of gas in it. On the highway I've picked up about 3 mpg. Believe this is due to the motor not having to kick out of OD all the time now when the wind comes up or a hill.

As for the gent that asked about install, didn't catch where you are but I motive gears, 5.38's, auto lockers and D44's. Independent shop, $1700.00. Proabably could have saved a few $$$$ had I driven down to the city to have them installed. Check around your area. These can be done yourself but if it is your first time, highly recommend having someone there that has done them a few times.

 

If you can find a pair of take-off Rubicon Dana 44s that have already been regeared to 5.13s or 5.38s for around $3500, it doesn't make sense to regear and add lockers to your stock Dana 30/44s.

Gears and overhaul kits cost $550. Labor to regear is rated at about an 8-10 hour job--multiplied by the going rate in your area. Selectable lockers cost about $2000 to do 2 axles. If the labor rate is $100/hr. You are looking at more than $3500 to regear and install selectable lockers with smaller and weaker Dana 30/44 axles.

If you can sell your stock axles for about $1000-$1500 and buy a pair of already regeared Rubicon axles for about $3500, it is a no brainer.

As far as gear ratio choice goes with an 07-11 automatic, with 35s you need 5.38 gears to run the same approximate highway engine rpm as a stock 6 speed Rubicon on stock tires. With 5.13s you won't have as much rpm (power and performance) as a stock 6 speed Rubicon. 4.88s with an 07-11 automatic would be a complete waste of money with 35s.