JLU_rubi18!
Well-Known Member
- First Name
- Jay
- Joined
- Jan 3, 2018
- Threads
- 4
- Messages
- 190
- Reaction score
- 186
- Location
- Seminole, Fl
- Vehicle(s)
- 2015 Jeep SRT Red Vapor, 2015 Jeep GC High Altitude Hemi 4x4
Regearing to 5.13 ( unless 40s )will be way too much gear for this platform. Those were gearset numbers for the JK platform and no longer apply to the 8 spd. The only thing flashing the computer does is change your speedo and your shift points to accommodate for the new fire diameter. It will help butnthe only way to truly add power back is through a regear. Personally I’m going to see how these stock axles do with 4.10s. Based on my experience with the JK 3.6 and auto I’m betting this handles 35-37s very well.I have had a number lifted trucks with oversized tires and reprogramming the ECU for the correct tire diameter will make the biggest difference in your overall performance. Yes, the JL does have an 8-sped auto and I have had a RAM 1500 with this transmission. The difference in tire diameter and actually speed is what really hurts the performance when you make the leap up to a 37” from a stock 32.5” stock tire. Once I’ve had the ECM “flashed” or added a programmer that allows tire diameter correction, this brings the vehicle back into its desired operating range. In actuality you should re-gear to a 4:88 or 5:13 gears for 37’s, but reprogramming the ECU for the correction in tire diameter would be the first step to get the engine back into it’s ideal operating range. I had Silverado on 35”s with a 6-spd auto and 3:73 gears, once I added the programmer and corrected for tire diameter, it was night and day difference. Ideally I should have re-geared to 4:10’s, but I never skipped a beat after the ECU was re-programmed. I wheeled that truck in the desert for 5 years with no issues?
...just my 2 cents?
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