Hi guys I just joimed today, and don't mean to sound pesky. I just got my 2012 unlimited on 35's do I need to regear or get a procal? I think I have 3;73 gears not sure though. Thanks and lovin the new ride!

 

You will need the Procal to recalculate your speedo at a minimum. I am running 35s with 373 on a 2011 with a 6 speed and it is fine. Do you have a 6 speed or auto? Welcome to the forum.

 

Will it help gas consumption as well?

 

I have a 2012 with 35's and running 4:10. My speedo was off by nearly 6 mph at 55 mph. I have the Rubi so it had the 32" BFG's. not to mention, the procal gives additional programming modes. It also corrects shift points in the tranny. For $150, it's worth it. Considering that would be about the same as a speeding ticket.

 

come again? does it really reflash the TCU as well?

 

The Procal is like replacing a speedometer gear in the transfercase of the TJ Wranglers. It does not matter what gears you have (3.21, 3.73 or 4.10) you should still buy a Procal to recalibrate your speedometer. It does not "change" per-say the shift points, it merely returns them to stock.

Basically, the computer in your Jeep will not tell the automatic transmission to shift properly if it is given false MPH readings by an improperly calibrated speedometer. The Procal correctly calibrates it.

The short answer is actually a question.... Do you want your speedometer to read properly? Do you want your automatic transmission to shift properly? If you answered yes to either, then yes you need a Procal.

 

Yes, what project06tj said. Returns the shift points to normal. Whether or not this occurs through software or it is a byproduct of speedo correction, I'm not certain. Logically, speedo correction would retain factory shift points.

 

Actually, if you think about it, the speed cannot be the only factor in shift points. When you put larger tires on, it essentially gears down the jeep. So, at 45 in first gear on stock 32's you'd be at 5500 rpm. But at 45 in first gear with 35's you wouldn't, because the tires are larger, meaning fewer rotations for the speed you're going. So just recalibrating the speedo isn't going to correct the shift points. That's why the tuner also corrects shift points, as they are based on engine revs.

 

I would say yes. Mine used to not shift into overdrive on its own. I had to manually shift up. Also, I believe the larger tires are not only messing with gearing and shifts but throttle position. Before it was sluggish, which was mostly due to shifting early(jeep thinks its going faster than it is). When it was shifting early, it felt like the motor was struggling to slowly get back to the rpm range. Kind of like lugging down the motor with a locked converter. Now its smooth sailing. Downshifts are smoother and upshifts are more in the desired rpm range.

 

Telling your computer your actual tire size also helps with the roll over and antiskid protection from my understanding.