I recently upgraded from 3.73 to 5.13 because I also lifted and went with 35's. BEFORE the regear, I drove for a week with the 3.73 .. ( auto tran). It didn't feel that bad and got around ... ok. ( I drove a TJ SE years ago ).

After the regear I could tell a difference, but not like a hemi like others have said. I think expectations get up too high reading regearing posts and stuff.

I then flashed it with my Superchip Flashpaq. I read enough to know this was going to be necessary with the auto tranny and bigger tires and the regear. Well, I can tell you I couldn't be happier.

It has taken the Jeep about a week or so to "settle in", but it is just driving great. mpg is down right now 'cause I tend to stomp on it and see what response I get. It does even better with O/D turned off, but holds speed nicely on the highway with some left... even in OD.

So, it really depends. Now my JK with it's flash and regear still does not have the torque or speed of my stk Chevy truck with a 5.3 V8. Just doesn't and never will. I'm ok with that. The JK drives like a Jeep. They weren't meant to be 4x4 350zx's. Trucks are trucks. They're not nimble and easy in parking lots.

I highly recommend the regear if you're up to 35's , esp in an auto tranny, and with that a programmer of some sort. I only can vouch for SC, but I'm sure the others are good too.

 

drove around for a long time with the stock 410's and 35's.....513's were one of the best mods i have done....I didn't expect hemi power, but there was a huge difference IMO....I also have the 6spd......

My brother has almost the identical Jeep to me, but an auto....when he did the 513's, he said it was a a big improvement, but if he could do it again, he would get 538's....he doesn't have the flashpack to change anything, so maybe after he gets that he'll be even happier...

 

I am sure this has been said, but until you get your speedo calibrated properly, the computer doesnt know you have different gears. So it thinks you are going one speed, and you are really going another.

Get your speedo properly calibrated and then try it out.

 

Maybe adjust with ProCal? It does make a difference when the JK's computer is set right.

 

I have 5.13s with 35s.

I can understand how someone might be disappointed with the power gain from from a Flashpaq, but the shifting and throttle response is vastly improved and hard not to notice.

 

well if u are that unhappy with them, then take them back out and run the stock gears, then we will get to hear you complain even more, wha wha wha

 

Re-calibrating with a Procal or other is a must espacially with an auto tranny... you will kill it rapidly if you don't ! Even just 35" with stock gears is aging the auto tranny by being constantly on wrong shift point !! (recomended less than 3% difference in tire. from stock 32" to 35", it is 5% difference on the circumference, thus on the indicated speed... and on shift points)

 

I missed that he had a Hypertech programmer as well. Have the shift points been changed for the larger tires and gears? I don't even know if the Hypertech is able to do this.

 

Yall need to remember too....regearing does NOT add power. All it does is give the Jeep more leverage to move at a given RPM. Sorta like using a long handle wrench VS a short handle one. You have the same power available, you are just able to apply it differently. Even with the reprogram, you're still not adding power. All you are doing is making it easier for the Jeep to move with the power that it does have (or not have).

 

I drove through Austin a couple of times. There are a lot of hills over there. I can see how the jeep would drop out of OD, no matter what gears you have. I found that 5:13 were a little too much gear for my 35's. Now that i have 37's it seems like a better match. Mine would come out of OD when i would climb bridges and stuff. I find that my jeep performs better with the 5:13s and 37's with the AEV Procal than it did with 5:13's and 35's with no Procal.

corey d