resharp001

That will really depend on your personal use of the jeep. With the 3.8L, you'd most likely be looking at 4.88s or 5.13s to get some power back. With 3.8L and 35s, I think it's a lot harder to overshoot your target. On the 3.6L, you can definitely get too low. For example, I have 3.6L and 37" Nittos.....I'm fairly aggressive offroad, and I don't have the benefit of a rubi transfer case. I went with 5.13 gears. I love the offroad benefit I get from them, but it kinda sux to be cruising 3k RPMs or higher at interstate speeds....and my fuel economy sux when doing so! Everything I've read is the 3.8L is less sensitive to higher revving RPMs.

Here are the 3.8L gear charts. Note that the tire sizes are actual measurements at a normal tire pressure. Two people with the same tire might have different sizes if one runs theirs at 27psi while the other is 40psi. Most tires are gonna measure less than the stated size. You'd most likely want to stick in the green zone on that chart for a decent mix. When referencing that chart, it's easy to see why most 3.8L with 35s end up at 5.13. You see 5.13's a lot less often with the 3.6L.

tmac834

I'll be sure to save that chart! Is there anything else that I need to look at changing/fixing if I re gear?

resharp001

Not really. Master install kits should include all the things you need to replace internally....seals, bearings, etc. If you were gonna add a locker or some kind of traction control, that would be the time to do it as it would change out the carrier, but that would open up a whole new can of worms….do you need it, which direction should you go with it, how much is more is it gonna cost, etc.

I guess if you were going to replace ball joints, that would be a good time to do so since front axle shafts will be pulled out to do the gears, thus giving you easy access to change the ball joints. And if you're going to pull the BJs out, if you wanted to put gussets on the axle, that would probably be the time. LOL, crap just adds up and up.

tmac834

Are lockers needed if I won't rock crawl as much as trails and river runs? Is there price range for lockers? Random question now but will I need wheel spacers at all either?

resharp001

It's been a long thread, don't really recall what wheels your working with. For a 35" tire you need 4.5" backspacing typically. 33" tire 5.5" backspacing....TYPICALLY. If you do need to run spacers, buy quality only along the lines of Spidertrax. Don't buy some cheap eBay pos spacer. A properly back spaced wheel will always be preferable when at all possible.

In regards to lockers, no, you PROBABLY don't need em for your use. A selectable locker will run ~$1k, that that probably doesn't make sense for your use. You MIGHT want to research truetracs and "lunchbox" type lockers. They are considerably cheaper. I would say this......if you go out by yourself....even doing water crossings or back roads, you should always be prepared to get yourself out of a jam. Even innocent situations can turn precarious in a moment's notice. Sometimes that means traction contol to help get through something, sometimes that means a winch to help, sometimes it just means having proper tools. Only you can make those decisions. I would look up truetracs and oter type lockers. You may or may not see one those as being worthwhile. "Selectable" lockers are not going to be up your alley for that use.

tmac834

Thanks I'll do some digging on those! Do I need to re gear right away when I pick up new tires? I know it'll drive differently if I don't but will anything crazy come up if it takes a month or two to get to regearing?

resharp001

Not really. You'll just notice decreased performance in your jeep in general. Keep in mind that if you don't calibrate the computer for change in tire size, your speedo, odometer, and fuel economy will be off a bit. Since you're planning to regear, you may as well pick up a programmer as you'll need it for gearing down the line anyhow. Some could argue you'll be putting a little additional strain on your auto tranny, but many drive with less than ideal gearing for years and years.