everyone qoutes the magical breaking point for needing 4.10's as the 1" difference from the 31'-ish tires most evry lifted KJ runs to the 32'-ish tires that get stretched on ( a total of .5" ground clearance increase-wow

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But if you look at the actual rpm difference throughout the RPM range, there is generally on a couple of hundred RPM difference: (1771 vs 1951 at 65 mph, for example..wow, what a change!!!!)
If you want off-road performance, skip the ego boost of that extra .5 inch of ground clearance and expense...although some here apparantly need an extra .5" everywhere they can get it. The only true huge jump in factory or near factory performance across the RPM range and increased on road/off road performance is manning up and learning to drive the 6spd. With the same size tires, your crawl ratio with stock 3.55 gears is far superior to the expensive swapped in 4.10's and you get better MPG to boot. 265/75/16 auto with 4.10's gets you a 31.56 crawl ratio where a 6spd with the same tires and STOCK 3.55 GEARS gets you 48.2, and you save a ton of money at the pump and on parts. Again, selling your auto and picking up a 6spd is your best bet for inexpensive but clearly superior off/on road performance. The locker cost is the about the same.
Many build for bragging rights, and their use of their KJ's clearly indicates that. If you want braggin' rights and poser-ability, you have plenty of models to follow. If you want performance, well, the answer was there from the factory. Sell your auto, buy the generally less expensive 6spd, and use the savings on lockers. Then blow the posers away by actually using your jeep and outperforming them at every measure!
I'd have to agree that many folks modify their Rigs for bragging rights and 0.5 inch of ground clearance extra is nothing to scream at!
But an automatic ****** has more towing capacity than a manual gear box
(Auto box: 5000 Lbs. towing limit/ Manual box 3500 Lbs. towing capacity.)
As well as easier to drive. (However, a manual in my opinion is better off road and more fun to drive!
A catch 22 situation!)
Better to have the automatic...
Especially for a gimp like me!
As far as 4:10 gears?
I don't know. Haven't tried them yet!
But if I gain 2-3 mpg, I'll take that.
Not to mention that the off road performance will be better. (Based on those KJ owners who have swapped to 4:10 and have posted their positive experiences!
Just my 0.02¢ worth...
As far as the cost involved to have ARB Lockers (and very possibly 4:10 gears installed)
I think $3400.00 isn't over the top for having somebody do the work.
I cannot install all the parts in the same amount of time that a 4X4 shop will do it in.
And our KJ is our only vehicle in the family and is needed as the daily driver!
That and I'm a lazy SOB who would rather pay somebody else to do the work and have a guaranty/warranty at the same time!
I called the Chrysler/Dodge/Jeep dealership we always deal with and they quoted me $1200.00-$1400.00 to have just the rear end rebuilt.
At 220600.0 KM I'd like to have the diff's fully refreshed and like new.
I am a total gear head and a real stickler for preventative maintenance and you will never hear me complain how much cash I dump into my vehicles to modify them and keep them in 100% mechanical condition!
Besides, our mall crawler needs lockers after last weekend!
That way I can justify a couple of ARB stickers on our Rig!:happy175: