Hi all, I'm hoping for some help from you all out there. I've got an 02 TJ X 4.0. I use it as my daily car, and for getting to places I like to go. 4WD is there as required, not for its own sake. I changed up to Dueler 9.50x30s, mainly for the extra clearance, and the performance and mileage dropped. I need to be doing over 80mph on the highway to tick above 2100rpm; below that there's no power for even the slightest hill. 80mph+ does neither my gas wallet nor my sense of "stay out of trooper radar" security much good (although here in Alabama 80mph is still usually pretty safe). However, driving anything near 70mph is pretty much pure 4th gear. So, I'm looking at swapping out the pinions for 3.54s, which is the next size up available. However, this seems to bring the rpm up higher than I'd like. Is there any other option?

Secondly, I'd like a locker or at least a good slippery diff to improve traction when needed - 4WD should be at least 2WD after all - but highway and general driving is important here - the locker will be used a zillionth of the time of non-locked. Which is the best way to go here? In the old days, when I drove land rovers before they became prissied up to wannabee look-at-me's, the wisdom was just to put a locker in the front diff, where it didn't interfere with non4WD with driving but was there when required. However, LRs had fully-floating axles (woefully understrength (but that's another long and oft-repeated story - never drive an old landrover without sufficient strong fencing wire to pull a broken axle out of a diff, or enough gear oil to refill the diff after splitting it to get the bits of metal out. Oh, yes - and always carry two spare axles). So given that TJ axles are not FF, would the advantage of putting the locker just in the front diff - no noise, wind up etc - be lost?

Lastly a whine and a tip. Can we march out the idiot who designed the placement of the wrangler fuel tank , and have him summarily shot? And all those who followed but haven't changed it. Now the tip. Hi-Lift jacks are great, but don't fit anywhere, despite all those expensive racks and other junk. (Another question - why does a bit of bent and welded steel cost $500 plus?) However, by taking off the plastic caps on the rear stock bumper, cutting a bit of the metal out, and drilling a couple of holes, a High-lift will slip sweetly in, held in place by two bolts. It's low down, not increasing the center of gravity height, as it does on roof racks, and directly accessible. Even adds a bit of weight at the rear end for improved driving with no load, and doesn't even interfere with the tag plate for those picky police states. If anyone's interested I'll post a pic.

My TJ came stock with 3.73s to turn the 30x9.5 switching to 31 made no noticable difference. the rubicons have 4.11 to turn 31s. getting 4.11 gears used might be very easy that is what the 4 cylinders come with (think ebay). 4.11 would probably be good up to 33" tires but might make it a touch more thirsty.

I think 3.92 may also be an option

the front axle does not disengage, so the only option up front is a selectable locker, or a Truetrac LS by detroit locker. a "real" locker is not an option.

in the rear you can do a get a little insertable locker to replace the spider gears in a stock case. I've hear normal lockers can be a bit squirly, its not street leagle but many say a rear spool is better.

another thing to consider; going to these different ratios could require a different carrier anyway.

Ibelieve I saw an add for 2 ARBs, gears install kits and a airpump as a kit for about $2000, and kits with a Trutrac and a detroit with gears for I think about half that.

Thanks (again) Groo. X's come with 3.07 gears - who knew? I didn't buy a sport because I couldn't find one with full soft upper doors, and didn't want to pay extra for wheels I didn't like. Not so sure now. It would seem something around 3.35 would get me back to stock revs, but 3.54 - plus a new carrier - is the highest around. With a 3.54 I beleive 31" tires will put me back closer to original, which was good - I could cruise all day at 75 and get 20mpg. Right now, cruise control is just a decoration.

As far as the locker goes, you're suggesting a Detroit selectable in the rear and a truetrac slippery in the front, right? (ARBs are good, but I think too expensive for my needs, and also there's a lot of extra gear involved - I like simple). Plus the gear changes, all done at once to save labor. This shouldn't affect cornering or other ride characteristics, or increase noise or drivetrain friction?

Thanks again.

in 97 3.55s came with the 30" tire package, it was changed to 3.73 from then on (my guess is for drivability). I think you might be able to use your stock carriers with 3.55s (don't know the cutoff point with the D35). but if you buy lockers for one ratio, you might have to get different lockers if you decide further upgrades are needed in the future. your not going to get you small tire mpg no matter what gears you choose.

the selectable lockers are just as much as the ARBs, an automatic lockers is cheaper.

The cheapest route would be the ebay 4.11s and a luchbox locker in the rear.

you might even find a set of axles with better gears cheap.

my dream locker combo would be to use the electric lockers, because I think it would be easier to deal with wires than airlines or cables. the aburn in the front and the detroit in the rear. the detroit goes from truetrac style to locked, but hase an external actuator. the auburn goes from open to locked, but its all internal.

I've heard the Detroit gearless can be used in the front, but I've never heard anything good about it.

for drivability selectable or truetracs all around. the truetrac is limited to 33" tires. I never realy aquainted myself in whats availiable for the D35, but I know you can get a Detrot C locker, an OEM clutch type LS and several of the selectables.