Willy16

Well, I have owned 3 Wranglers (YJ, TJ and now JK), 2 XJ Cherokees, Countless performance cars (SRT, GT500, Marauder) that were all heavily modded. My XJs and TJ were all lifted heavily. My YJ Islander (which I still have tucked away) has never been lifted. But, trust me, I know why people re-gear on both off-road and speed applications...I've done it more times than I need to admit. And for many scenarios, it is necessary. Some of which you mentioned - rock crawling is a huge example. Or like you mentioned, using all of your gears again (to pass people!). But, I will stick to my initial comment on why people think it's necessary. I can only speak to what I have owned and my real world advice. My Jeep on 37s will never see 85mph, and I literally laugh out loud when you said you drive it normally 80-85mph. That fits into my exact scenario of why people tell you that re-gearing is a must. For my Jeep, re-gearing is not necessary. Not because I don't know what I'm missing. Because I've been on the other side and can say, on my XJ or TJ it was necessary. But with my JK, it is not. I will even honestly say - based on my driving... I can not tell a big difference in driveability of mine going from stock 32" BFG Muds to the 37s. My biggest adjustment is braking hands down. I drive it easy and slow. Believe me, it's all relative. I understand someone may jump in my drivers seat and say "Good Lord! How do you drive this snail!?" It is not slow to me and for how I drive - I love it. It actually feels more like a Jeep to me now on 37s - than with the 32s. The 3.6 with 3.73s felt too powerful for the stock 32s period. And I think that goes to my point of how people drive now... insanely. And when I say people drive insane now - for example... take a road trip down any interstate in this country. When you see a truck or SUV pulling a trailer...with tires rated for 55mph (Stating so ON the trailer!!) flying along at 80 in the fast lane...weaving in and out, passing people. That is what I mean by insane drivers. I think lifted Jeep's...as already a vehicle prone to rollovers, driving crazy (let's say, like a 17 year old testosterone crazed kid racing his Subaru WRX STi) is nuts. But, that is just my opinion, which is probably not going to get alot of likes in the year 2018...but to each his own.

If you daily drive and are a slow driver, parking lot queen, mall crawler. There is very little applicable advice to gears unless you like to race. Period. The 37s do not strain the engine/trans combo on a newer JK with the trans coolers. If you live in the Rockies, or the Appalachian area, I can definitely see a benefit to gearing as you climb mountains. Downshifting will become a bear. If you live in the flatlands (most of America) and you don't off-road... keep your 3.73 or 4.10s. In my circle of commuting, my Jeep NEVER has to downshift. And I also never hit 80+mph. And to comment on the trans. straining - I mean, unless I see some FCA case studies that show 37s are prematurely causing trans or engine failures, then I believe most pro's and con's stories are mostly anecdotal. Most people are going to keep their Jeep for what...? 5-6 years? They may lift it, throw 35s or 37s on it... trade it in after set period of time, and never have a transmission or drive train issue at all. At least that is how real world goes. Rarely people keep their vehicles for 20+ years and put 600,000 miles on them. But I will 110% agree, heavy offroading will break something quickly on 37s... geared or not. I mean I know people stock height...thrown 33's on ...and break stuff. That is part of the off-road game period. You will break crap, guaranteed....if you are pushing it. Jeeps, Hummers, FJ Cruisers, etc.... they all break. And alot can be attributed to people not knowing how to drive it offroad as well. But if you heavily off-road, I do believe you are spot on, it will definitely help rock crawling. I think even with an automatic, you will have issues on heavy off-roading without a taller gear, period. I also agree with your Rubi T-case comment. That is one of the best things you can do for rock crawling.

Sorry to digress, OP, it's all up to you. If you know you will be driving it off-road and want to visit Rausch Creek....Mt. Morris.... do some real rock crawling - get you some gears. And BoraBora's list is spot on, period if you plan to utilize your Jeep like a Jeep. But if it's just hauling the family up to the local DQ on the weekends and driving you to work - you may want to skip em.

DarthDaver

Just re-geared the 2016 Wrangler to 4.88 w/37" tires. Now it seems as though the transmission shift points are off, no power at all to the wheels it seems. I just ordered the superchips flashcal that i read about in one off these threads...will this fix my issue?

Sorry for the weird posting, waiting on an admin to approve me so had to reply/post on another thread...

resharp001

You reprogrammed the computer for the new gears right? Have you adjusted the tire size or that is what you're waiting on the programmer for?

karls10jk

You can accomplish the same thing (and more) with Jscan and the Bluetooth piece, but yes, you need to tell your computer that the gears and tires have changed otherwise it's using wrong info and getting confused.

DarthDaver

The programmer arrives today, I believe the jeep is in reduced power mode, can i use the programmer with it in this mode? Currently waiting on the mechanic to take it out of reduced power mode.

I realize I probably should have had the programmer BEFORE the re-gear but didn't realize it was needed..."facepalm"

resharp001

Yes, you're in limp mode. As Karl noted, Jscan would be a better option for you at about $35 total cost for BT dongle and the app license, and the functionality of jScan is more dynamic than the SC programmer.......if you can return it maybe.

You just need to set the gear ratio and tire size in the computer and you'll be set.

DarthDaver

I'm surprised after all the post's I went through I never saw the Jscan as an option...too late now I need to drive this thing, leave ends tommorow and I need to get to work lol.

Should I wait until limp mode/reduced power mode/whatever it is be fixed by the mechanic BEFORE I use the programer?

resharp001

The only way a mechanic can "fix" that is to reprogram the computer. if they can reprogram the computer for you, then you don't need to use the SC and could return it. If you can wait to get the SC yourself, then there is no reason for you to take it to a mechanic. it's a simple computer issue. the jeep thinks it has the old gears still but all the mechanical information the computer is being sent due to the new gears don't make sense. Setting the gear ratio and then the tire size with your programmer is a simple thing you can do in a few minutes yourself.

DarthDaver

Ok, thanks a ton to all of you guys. I just got the jeep and am learning quickly there is HUGE learning curve, glad there are guys like y'all out here to help us newbies out!

resharp001

Indeed there is! I suspect you'll be back for some more things along the way since you're rollin on 37s. There's typically a few of us regulars hangin around with quick response. Take some pictures along the way and consider submitting an entry in the featured jeep of the month contest