My experience with JLU Sport with auto, 3.43 gears, Mopar 2" lift and 33" AT tires

2500 hd

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I have an appointment to recalibrate the tire size Friday morning. I hope it makes a huge difference but I am not thinking it will.
Removing battery power is an interesting thought though. May try that after this weekend.
I live in NC also. My dealer said they had to wait on some software to be able to recalibrate mine..
I’m not sure sure they know what they are doing.
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Yoyo27983

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I live in NC also. My dealer said they had to wait on some software to be able to recalibrate mine..
I’m not sure sure they know what they are doing.
They don't! Here is what happened to me today. I had an appointment at 0830 to have them recalibrate the speedometer. At 1230, they call me to say they can't do it because the software has not been upgraded to allow them to do a 2018.,I then informed them about the YouTube video by JEEP INFORMANT that details exactly how to perform it. I carried the service manager into his office and showed him the video. He then followed it step by step up to the point the video ended. They then had 4 people at my jeep trying to get the configuration downloaded to the BCM. They then took it for a test drive. When he came back, they took it back to a service bay and I asked the tech what was wrong. He said it still appeared to be wrong. I told him how I measured it by my phones GPS speedometer app and it was off by 2mph. He then borrowed a phone that had that app from another tech, I had left my phone at home. Then we went for another test ride. I noticed that now the Jeep was not able to go to 7th gear and the mpg gauge was decreasing from 16mpg and was now 14mpg. This was only about 4 miles. The gpd was now showing 54mph and the jeep showed 55. When we got back, he started looking at the tires and said he smelled brakes burning. He found the passenger rear was at over 600 degrees. The driver rear was 94 and both fronts were 125. I left the damn thing again and took a loaner home. I asked the service manager to not charge me the 125 for the recalibration since I had been there all day and he said he would have to charge me. At that point I told him that was fine and that I would only charge him 125 for showing them how to do it. He then walked off and said they would take care if it.
 
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Yoyo27983

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Right. And it should match. Your computer is still off. You are calculating your mileage based off your odometer which is wrong. You drove more miles than you think you did.

-Eli
Eli,

You are correct! My bad. A close friend gave me a schooling on that also.
 

Jeepsterfreak

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With all else being equal, why does a 2-3” lift cause a decrease in mpg? Is it due to more air traveling below the vehicle?
 

Arrowhead

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When we got back, he started looking at the tires and said he smelled brakes burning. He found the passenger rear was at over 600 degrees. The driver rear was 94 and both fronts were 125.
Well obviously a dragging brake caliper will kill your mileage. The emergency brake cable is probably hanging up from the lift install, that's probably why the MPG took a dump in the first place.
 

2500 hd

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They don't! Here is what happened to me today. I had an appointment at 0830 to have them recalibrate the speedometer. At 1230, they call me to say they can't do it because the software has not been upgraded to allow them to do a 2018.,I then informed them about the YouTube video by JEEP INFORMANT that details exactly how to perform it. I carried the service manager into his office and showed him the video. He then followed it step by step up to the point the video ended. They then had 4 people at my jeep trying to get the configuration downloaded to the BCM. They then took it for a test drive. When he came back, they took it back to a service bay and I asked the tech what was wrong. He said it still appeared to be wrong. I told him how I measured it by my phones GPS speedometer app and it was off by 2mph. He then borrowed a phone that had that app from another tech, I had left my phone at home. Then we went for another test ride. I noticed that now the Jeep was not able to go to 7th gear and the mpg gauge was decreasing from 16mpg and was now 14mpg. This was only about 4 miles. The gpd was now showing 54mph and the jeep showed 55. When we got back, he started looking at the tires and said he smelled brakes burning. He found the passenger rear was at over 600 degrees. The driver rear was 94 and both fronts were 125. I left the damn thing again and took a loaner home. I asked the service manager to not charge me the 125 for the recalibration since I had been there all day and he said he would have to charge me. At that point I told him that was fine and that I would only charge him 125 for showing them how to do it. He then walked off and said they would take care if it.
What part of NC is the dealer you are going to ?
 

George999

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Youre actually getting a little better mpg than you think. After you calibrate you'll probably see an average of 18 or so. At least that s what I average.
If you don't mind my asking what did you set the tires to, 32.7 or did you go to the 33.047? Looks like you have the rubi wheels and tires on your profile pic.
 

WalkingJL

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Honestly I don't t remember. I have 35's now or I'd go out and check.
 

George999

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Yoyo27983

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Well obviously a dragging brake caliper will kill your mileage. The emergency brake cable is probably hanging up from the lift install, that's probably why the MPG took a dump in the first place.
I am hoping you are correct, they kept it and gave me a loaner for the weekend. Another weekend without the jeep.
 
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Yoyo27983

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With all else being equal, why does a 2-3” lift cause a decrease in mpg? Is it due to more air traveling below the vehicle?
I think it was more that it leveled the Jeep making it even less aerodynamic more so than the extra air underneath, It probabley is a combination of both. It sure made a bigger change than I was expecting.
 

Jeepsmashin

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OP I'm curious to see what a JL looks with a 2 inch lift and 33s. Post pics?
 
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