Are there any issues regearing the axles with an automatic transmission? Are there gearing presets in the ECM? I never considered this but ran into someone who had this issue on a 2012JK. New to the forum and trying to figure this out. Thanks
Are there any issues regearing the axles with an automatic transmission?
- Thread starter JoeTex
- Start date
Nah, you can regear and it’ll be just fine. The transmission shifts and locks the torque converter all based on hydraulic pressures felt from the throttle and rpm. You may notice it shift earlier but using the pedal more will still downshift it like normal. This is assuming the transmission bands are adjusted properly - a good procedure to do if you haven’t ever.
What tires do you have and what are you looking to gear to?
What tires do you have and what are you looking to gear to?
I have 31s and looking to move up to 33s when they wear out. Not planning on going any bigger but you know how that goes. I’d like her to be “trail ready” but I need to drive her to and from the trail. I have no idea what to gear to. There’s a chart out there to give me some idea so we’ll see. It’s my first project so trying not to get too carried away too fast. I’ll put “adjusting the bands” on the list.
I would suggest trying your best to choose between 33’s or 35’s long term and settle on one if you can….as for ratios I would go with 4.10s on 33’s or 4.56 for 35’s. Those are well known “ideal” setups for the 3 speed 4.0.
You’re welcome. I don’t know what your current setup is with lift and all, but keep in mind that 33’s or 35’s will send you down the larger axle, tall lift, driveshaft mods to suit the lift, etc rabbit hole. Just be prepared that one thing inevitably leads to another. YJs came factory with 27’s on most trims and can only really step up to about a 30” without mods, and only a 31” with minor mods. 33” is new territory that starts making it a real good idea to make supporting changes to run the tires.