gnarly_mike

I am building with 5.13 ratio. Thats why I don't want to have to throw the 14 b in half ass built without the shaft or locker or wheels I wanted, and then have to regear the front end to match until I get a front 60 built.

If I wanted to regear the stock axles I never would've bought two more stock axles I would've just redone my original ones.

Driving with 37s on 3.21 will be absolutely miserable.

gnarly_mike

Nope, the jeep was stock with low miles when I got it, stock tires. I put the 37s on and never had a problem other than incorrect speedometer. Never reprogrammed it.

You don't HAVE to reprogram it unless you don't want it incessantly hunting for gears on long highway inclines, or your speedometer being off by around 9mph.

I never reprogrammed mine because it drove fine, and I knew it was about 9mph off because I calculated it. Never cared to spend the money for programmer at the time and then just never ended up doing it.

Once I have 5.13 axles and 40s I will definitely reprogram.

jadmt

on a 12 and up jk with auto having your speedo off by 10mph is going to screw up your driveability no matter what gears you have. also you don't need the vin to check the grears just jack up your jeep and spin the tire and count rotations compared to what the drive shaft is rotating.

kejtar

I think saying it drove fine is a bit of a stretch as with the screwed up shift points for these tires you were putting more strain on the engine and transmission but it's your drive train
Additionally it would be 9mph at a specific speed as your offset really is a percentage based on the difference of the tire circumference.

Getting back to issue at hand. If you still have check engine light pull codes using a reader. Also since you are looking to upgrade the axles and gears consider investing into a gizmo that will allow you to modify tire size and gear ratio. You will need it anyways.

resharp001

I don't disagree. My previous post was just in reference to you're gonna need a tuner anyhow......and may as well get one and make the best of the current situation....unless the axle's previous owner is willing to give you your money back for em. Kinda just make the best of a bad situation. I'd be frustrated as well if they were supposed to be 3.73 and are not. Time to confirm one way or another. IF they are not, and the person who sold em was a friend, maybe you guys can work something out in regards to a reduced price at least.


If they are 3.21 gears, at least with a tuner the jeep would be driveable while you build out your 14b. Not ideal, but serviceable at least as transportation while you build. I sure hope that is all it is.....gearing/computer issue and not something bigger.

gnarly_mike

My drivability was fine. I would never have gone 2 years this way if it was not. I manually shift my Jeep most of the time anyway as I learned to drive on a manual tranny and drove one for 8 years until I got the Jeep, habit I guess, and also makes it worlds better than driving a 3.73 geared Jeep on 37s in automatic.

If I'm not mistaken, that gear check trick won't work with non stock size tires. I could be wrong. Any who, it will be hard to differentiate by eye between 3.73 and 3.21 possibly. I heard something about counting teeth on the ring gear but idk if thats legitimate

gnarly_mike

Yeah, I am 99% sure its just the computer behaving weird due to 3.21 gears with a computer that thinks they are 3.73. It will suck but yeah it would be much better to find out I have 3.21 gears than finding out I have some mechanical problems.

The guy I got them from is just a local guy, owns a couple shops around here. Air Force veteran, seemed like a good dude. If they are 3.21 Im sure he would understand if I were to request he give me some of my money back. Maybe not. Who knows.

About to order a programmer to sort this out, I just haven't decided which yet. Don't want to spend for the $300+ ones.

resharp001

I have a Bully Dog....can tell you don't get that as it's just not super user friendly. I have used a Superchips Flascal F5 unit before and it was a nice interface


That hub is turning just the same regardless of what size tire is mounted on it. It might not be as obvious as trying to determine if it was 3.21 vs 4.56, but I'd think you should be able to tell. Put a piece of tape of something on the tire.....turn the DS by hand 3 times.....did the tire make almost a full rotation, or does it take almost 4 DS rotations to turn the tire once?

jadmt

Gears are mechanical tire size won't change the gear ratio only the effective ratio. Rotate tire 10 times count rotations of the driveshaft. Is it 32 or 37?

gnarly_mike

Update. Got a superchips tuner in today and told it 37s with 3.21 and the jeep drove normally and the check engine light went off.

I relayed this info to the guy I bought axles from and he said that it was strange because he ran a 3.73 tune on the axles.

I might go out at lunch later and see what happens if I type in 3.73.

Does this make any sense? Could it run both ways? What if they ARE 3.73 and it’s running on 3.21 tune? Either that is the case, or the guy ran 3.21 gears on 3.73 tune...unless he is totally bullshitting because he sold me the axles in the first place knowing they were not the ratio he was saying they were.

I feel like I financed his little SEMA trip because it wasn’t like a week before....maybe he was being a dickhole and selling me the axles as what I needed when he knew they weren’t, because he just wanted money for SEMA.

he’s an Air Force vet and business owner. Didn’t seem like a liar. But maybe he is.