So i pulled the trigger on Yukon 5.13s, and I have a few questions, I have a 3.8l Auto. 1) what kinda MPG am i going to see I do alot of highway driving? 2) what causes the dana 30 to fail? I love to go wheeling but being my DD I wanna make sure it doesnt break. 3) should I put a selectable locker / limited slip up front, my theory is if I have all 4 tires going I can crawl with less gas pedal? or should I leave it open diff?

 

I went with an Eaton True Trac LSD up front gives you the benefit of having some type of traction device up there without the stress of a full locker on the 30's small R&P, I couldn't really justify the cost of selectable locker up front for the type of wheeling that I do.
My plan was to put TT in the rear and an Aussie up front but the front TT was cheaper than replacing the carrier and buying the Aussie. No regrets with this setup so far

 

So what size tires are you running. Usually when you get the tires to spin up front and then they catch that's when they usually snaps the drive shaft

 

315 75r16 duratracs

 

1) Too many variables to say what mileage you should expect. Read through a few dozen of the MPG threads and find a post from someone with your model and a similar build, who lives in a similar area, who drives the same way you do, who ... etc.
My assumption? You should pick up an mpg or two. Even being at a higher rpm, you'll be able to stay in OD longer without all the tranny downshifts.

2) Again, variables. General offroad use, and even hitting curbs and potholes can bend the housing. For the gears, a bad install has to be near the top of the list. And spinning a tire which catches and stops suddenly can certainly ruin your day.

3) Up to you and your budget. There is no way I would put a $1000 selectable in a d30. Some people like lunchboxes up there since they are cheap and not noticeable when in 2wd. (I live in an area with winter weather so I personally won't put another auto-locker in front, that was an expensive mistake). Which leaves the TrueTrac l/s. Plenty of threads on this option. Low price with very favorable reviews.

 

I have toyo mt 285/75/17about 97lbs ea.and auto 373 gears and I get about 16 miles to the gallon Highway.

 

I am in the same situation I am going to eventually get a PR44 for the front but for now I'm just going to build my dana30 and then when I do get the PR44 put it on my wifes JK or sell it

There are 4 major changes I plan on doing to my front dana 30
1. Rock Slide Bombshell kit - Its the outer sleeve reinforcement, inner sleeve kit, and knuckle gussets
Rock-Slide Engineering AXBS100D44 - Rock Slide Engineering Bombshell Kit for 07-13 Jeep® Wrangler & Wrangler Unlimited JK with Dana 30/44 Front Axle - Quadratec
2. RCV Spline CV Axles - These eliminate the U Joint that according to them is 2x stronger than stock they also have a "no questions asked" warranty
RCV Performance Products CVJ30-JK - RCV Performance Ultimate 27 Spline CV Axles for 07-13 Jeep® Wrangler & Wrangler Unlimted JK with Dana 30 Front Axle - Quadratec
3. ARB lockers - This is the kit I plan on buying because its both dana30 front and dana 44 rear
ARB Air Locker with Compact Air Compressor for 71-13 Jeep® Vehicles with 27 Spline Front Dana 30 & 30 Spline Dana 44 with 3.92 and Numerically Higher Gear Ratio - Quadratec
4. G2 ring and pinion - I plan on going 5.13 and 35 or 37 inch tires

Any one else have any other suggestions to make this thing bullet proof???