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Old 05-24-2019, 07:39 AM
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2015 jk shift points

Iím new to this forum and a new owner to this 2015 JK with 20k miles. Itís bone stock and I hate how the automatic shifts to the highest gear possible causing the engine to bog down to just above idle when cruising. I find myself manually downshifting driving around town. If it had a tow/haul mode so I could stay in the ďpower bandĒ Iíd be happier. Iíve seen the discussion on the pedal commander, called superchips, and have performed the pedal recalibration procedure. I know these jeeps are very underpowered and are trying to achieve maximum fuel economy (ha). Any help here would be appreciated, I canít be the only one who has had this concern.

Thanks

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Old 05-24-2019, 07:43 AM   #2
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What gearing and what size tires do you have?

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Old 05-24-2019, 08:52 AM   #3
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Quote:
Originally Posted by mommymallcrawler View Post
What gearing and what size tires do you have?
He said he was stock. I have a 15 JKUR with an AT and 3.73 and my friend has a 12 JKS with the AT and 3.21 gears. I find both of them to be adequately powered. The AT wouldn't put you in the "wrong" gear and it should downshift pretty fast when you push the pedal. Also if you think it's underpowered, I will take you for a ride in my 09 with a 6sp, or better yet get a ride in a 2.5L YJ or TJ. That should change your mind.
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Old 05-24-2019, 08:59 AM   #4
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Sorry I missed the "stock" part. *goes to reading fail corner*
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Old 05-24-2019, 09:03 AM   #5
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I just traded in my '07 JKU for a '15 and am very happy with the way it drives. Getting much better mileage and smoother shifts. They are my daily driver around town and short highway stretches.

Only thing I have to get used to is the 'Auto Stick'. I got in the habit of driving with my right hand on the shift lever and occasionally inadvertently down shift when sitting at a stop or making turns (it has a very light touch to shift)...causing me to wind out the engine when I get going
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Old 05-25-2019, 09:33 AM
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It has the 3:73 gears. When Iím cruising around town the transmission goes to fourth gear at 25 mph and lugs near 1000 rpmís. Donít get me wrong, I love the little guy. I just have to plan my merges onto the highway and am reluctant to tow a trailer. Just curious if the shift points could be adjusted. It feels decent when I use manual mode.

My last Jeep was a Ď78 CJ7 with a 6.6L and a TH400 trans. that went in after I let the smoke out of the stock 304ci. Iím just used to naturally aspirated 6 cylinders.
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Old 05-25-2019, 10:18 AM   #7
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Something is not right. I have a '17 Chief with the 3.73s (max tow pkg) and it never gets that low on RPM unless I have my foot off the gas and it's coasting down in speed. If I get to 25MPH and touch the go pedal even lightly, it will downshift.

Run your build sheet here (it says Ram, but works for all CDJR vehicles):
https://fcacommunity.force.com/RAM/s/equipment-listing


If you are interested in the original window sticker, you should be able to download it here (note: it does not work with Firefox, but does with IE11) just backspace delete the Vin that is in the link and enter yours:
https://www.wranglerforum.com/f202/2...s-2363221.html


If your Jeep has larger than stock tires and the computer has not been reflashed, then that could be the issue. Sports came with 16" steel wheels and P225/75R16 tires (29 inches tall), most Sport S Jeeps came with 5 spoke alloy 17" wheels and P255/75R17 tires (32" tall), most Saharas came with P255/70R18 inch tires on 18" alloy wheels (32" tall) and Rubicons generally came with LT255/75R17 inch tires on 17" alloy wheels (32" tall).


The Pentastar 3.6L qualifies as a "normally aspirated" engine since it does not have either a turbo or super charger. It does have Multi point fuel injection as do most engines. Believe, me, if the computer is set right, the 3.6L with 3.73s will push you back in the seat. It won't outrun a Rubicon with 4.10s (option with auto) but will definitely run off and leave a JK withe 3.21s I had a 2015 Sahara with 3.21s and while it was not all that fast, it was nowhere near being a dog.

With 32" tires (assume Sport S, Sahara or Rubicon) and 3.73 diffs with the automatic in 5th gear at 1000 RPM you should be doing close to 30 MPH. Again, assuming 32" tires in 5th gear, to get to 25 MPH at 1000 RPM the diffs would have to be 4.55:1.

Have you calibrated your speedometer with either a stand alone GPS (phone or dash mount - cannot use the built in GPS as it uses the speedometer for the speed) or with the old school of timing between mile markers?

Giving us the exact model JK and the exact tires that are on it would help.
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Old 05-25-2019, 11:39 AM   #8
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Quote:
Originally Posted by Judogold View Post
It has the 3:73 gears. When Iím cruising around town the transmission goes to fourth gear at 25 mph and lugs near 1000 rpmís. Donít get me wrong, I love the little guy. I just have to plan my merges onto the highway and am reluctant to tow a trailer. Just curious if the shift points could be adjusted. It feels decent when I use manual mode.

My last Jeep was a Ď78 CJ7 with a 6.6L and a TH400 trans. that went in after I let the smoke out of the stock 304ci. Iím just used to naturally aspirated 6 cylinders.
1000 rpm is not lugging a 3.6. The computer tells the transmission what the "best " gear is.
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Old 05-25-2019, 12:31 PM   #9
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OK. It's 95 degrees outside and too hot to work. So, I took the Chief out on the road in front (no traffic) to make a few observations.

Starting in drive coming out of my drive and accelerate to 25 MPH. When I ease up of the pedal, the RPM comes down in and stabilizes at 1000 RPM. But, as soon as I push even slightly on the pedal, the RPM jumps up to about 2000 to accelerate.

Using the manual gear selection, in 4th gear, at 25 MPH it indicates 1000 RPM. It will not go into 5th. Dropping it into 3rd, at 25 MPH it indicates just under 1500 RPM.

This is consistent with what the formula for calculating speed at a RPM/GRatio/Diff Ratio and tire size tells me. At 1000 RPM putting 1.00 (4th gear) in for the Gear Ratio indicates 24.7MPH and putting 1.41 (3rd gear) indicates 26 MPH.

In drive, driving slowly at 25 MPH, 1000 is on the tach, but the slightest pressure and it jumps to about 1500 (downshifted to 3rd) which would give me more power to accelerate.

OP - if I am reading your post correctly, when driving slowly, at 25MPH the tach indicated you are at 1000 RPM. But attempting to accelerate, it does slowly which would indicate that it is not downshifting.
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Old 05-25-2019, 08:56 PM
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The 2015 is a stock Rubicon with 255/75-17 tires 3:73 gears. I did get the build sheet from FCA. With a Garmin GPS, cruise set on the freeway, all three readouts(dash digital and analog needle) are within 1 mph of each other. Air filter clean, no CEL, no pending codes, all hoses and wires connected, all fluids fresh and full. I accidentally got it into limp mode when I rolled backwards down a hill in drive, but that reset itself.

I wouldnít say it jumps into a lower gear when Iím cruising around town at 25 mph. then trying to accelerate. Pinning me to the seat it definitely doesnít. Perhaps Iím a candidate for the pedal commander, turbo or supercharger, or dare I say an LS3 swap. Still only 20k + miles on it.
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Old 05-25-2019, 09:44 PM   #11
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I have a 2016 Rubicon stock, with 4.10 gears. I found the transmission to be fantastic, in fact the best A/T I have ever owned. It always seems to be in the right gear. I wonder if the difference is in the gearing.
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Old 05-26-2019, 06:45 AM   #12
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The OPs only other experience with Jeep ended up with a 402 SB Chevy backed with a TBH and he's comparing it to a new stock 3.6 Jeep and calling the new Jeep under powered and complaining about how the trans works. Nice trolling job. Seems to have hooked a few. And in the first 3 posts.
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Old 05-27-2019, 01:25 AM
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I love this site and the wealth of knowledge you all provide, you helped me with my leaking door seals, provided me with part numbers that the dealer should install under warranty and many other details specific to my Jeep. I especially like the lift conversations as this is something I want to do in the future. Thank you all for your input.

I will consult a transmission shop as well as have another wrangler owner drive my truck to see if things feel normal to them. I drive 30+ rental vehicles a year for work travel, from Mercedes to Kia and something is not right here. I am not a troll.

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Old 05-27-2019, 02:16 AM   #14
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18 JKUS 3.21 stock
I think I know what you are talking about, and why you say it is "underpowered".
This transmission doesn't downshift right, it stays in the higher gear till rpms drops below 1500, now under slight acceleration from this "eco mode" it wont down shift like any other normal transmission would ( I tested on the same road different cars to compare) it would keep the high gear until the motor will shudder/ping.
The only solution i found is to manually downshift in advance.
Another solution is to regear.
I have a suspicion that all jeeps get the same transmission software without regards to wheel size and gear ratio.
Another possibility is that the pedal is made less sensitive for off-road use and is not receptive to light application. When switching cars i have the feeling that gas pedal is too sensitive compare to the jeep.
Manual downshift works for me and I think transmission will learn it and will start doing it automatically after a while.
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Old 05-28-2019, 06:55 PM   #15
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The AT has overdrive but for a 2015 there is no button to disable it. When I went looking for a newer jeep I had test driven a few automatics and I did not like how they handled. All but one had larger than stock tires and had not been recalibrated, and trying to use the manual shift, something I was not used to, did not help, so I purchased a manual and no regrets. It sure did feel weird though driving a Jeep w/AT after driving Jeeps with nothing but sticks for the last 20+ years.

A few suggestions in the thread linked.

https://www.wranglerforum.com/f274/3...x-1293353.html

https://www.wranglerforum.com/f274/3...ts-197312.html

Quote:
Originally Posted by chargermop View Post
I know this will sound crazy but try this I promise it works it'll be like driving a whole new vehicle you'll have to do it every time it starts to feel sluggish not that often but it's quick and easy and makes a world of difference.


1) Insert ignition key and turn to "ON" (not start).
2) Wait for all idiot lights to go out. Check Engine Light may remain on.
3) Slowly depress the accelerator pedal all the way to the floor.
4) Slowly release the accelerator pedal until it's all the way back up.
5) Turn the ignition key to "OFF".
6) Start the engine.
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Old 05-28-2019, 09:00 PM   #16
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2015 jk shift points

Sounds like a lazy computer. Take that pony for a good spirited cruise and stomp er to the floor a couple times on the freeway. That will wake her up. If you rather not do that pull the battery cables touch them together for a few seconds to discharge retained power, leave them disconnected for 10min. That will reset everything and will cure a lazy computer.
The computer is adaptive. If you continually drive it easy to save gas it will mimic your style. You need to step on it once in awhile and I do mean step on it.


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Old 05-29-2019, 11:59 PM
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Thank you for the links Sarkaukar2000. Sounds like I’m not the only one with this issue. I’ve done the throttle recalibration procedure with no success. I will try the battery disconnect and go out and romp on it, it’ll be fun anyway. I may be a candidate for the pedal commander if all else fails. My recent trip to the dealer for the airbag recall didn’t provide me with any information on my software being up to date. They did plug it into their computer though.

The best thing I’ve read so far is the how to on the fun switch. That is another thing that has bugged me with the nanny programs. I like the vehicle responding to drivers input and not controlling it for what they think is my best interest.
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Old 05-30-2019, 12:26 AM   #18
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TCM ADAPTATION - NAG1 Only
The adaptation procedure requires the use of the appropriate scan tool. This program allows the electronic transmission system to re-calibrate itself. This will provide the proper baseline transmission operation. The adaptation procedure should be performed if any of the following procedures are performed:

1. Transmission Assembly Replacement
2. Transmission Control Module Replacement
3. Clutch Plate and/or Seal Replacement
4. Electro-hydraulic Unit Replacement or Recondition

1. With the scan tool, reset the Transmission adaptive's. Resetting adaptive's will set the adaptive's to factory settings.

NOTE:
For Upshift adaptation, the Transmission temperature must be greater than 60įC (140įF) and less than 100įC (212įF). Failure to stay within these temperature ranges will void this procedure.

2. Drive the vehicle until the transmission temperature is in the specified range.

3. Perform 4 to 5 coast downs from 5th to 4th gear and then 4th to 3rd gear.

4. From a stop, moderately accelerate the vehicle and obtain all forward gear ranges while keeping the Engine RPM below 1800 RPM. Repeat this procedure 4 to 5 times.

5. Obtaining 5th gear may be difficult at 1800 RPM. Allow transmission to shift into 5th gear at a higher RPM then lower the RPM to 1800 and perform manual shifts between 4th and 5th gears using the shift lever.

6. The TCM will store the adaptive's every 10 minutes. After completion of the adaptation procedure make sure the vehicle stays running for at least 10 minutes.

7. It is possible to manually store the adaptive's under the 10 minute time frame using the scan tool Store Adaptive's procedure.

Driving Style Adaptation:
The shift point is modified in steps based on the information from the inputs.

The control module looks at inputs such as:

1. vehicle acceleration and deceleration (calculated by the TCM).
2. rate of change as well as the position of the throttle pedal (fuel injection information from the PCM).
3. lateral acceleration (calculated by the TCM).
4. gear change frequency (how often the shift occurs).

Based on how aggressive the driver is, the TCM moves up the shift so that the present gear is held a little longer before the next upshift.
If the driving style is still aggressive, the shift point is modified up to ten steps.
If the driving returns to normal, then the shift point modification also returns to the base position.

This adaptation has no memory.

The adaptation to driving style is nothing more than a shift point modification meant to assist an aggressive driver. The shift points are adjusted for the moment and return to base position as soon as the inputs are controlled in a more normal manner.
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Old 05-30-2019, 12:37 AM   #19
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I highlighted the procedure for the transmission adaptation without the scan tool.
First of all negative terminal of the battery have to be disconnected for 5-10 min to flash previous adaptations. Then perform the "relearn" procedure for the throttle and after TCM adaptation procedure. In my case didn't solved all the issues but throttle response and upshift points improved significantly.
I would also suggest cleaning the TB before performing all above procedures.
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Old 06-01-2019, 08:58 AM
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Thank you for all the details, that is quite a procedure. I disconnected the battery to reset the PCM, the transmission stays in first and second a little longer now. But itís fovorite thing to do is find the highest gear. It will hit 5th below 1000rpms. then requires 1/4 throttle to downshift.

I have a long 25mph road I have to drive everyday with stop signs and up grades both ways. This is where it bothers me the most. It canít maintain 25 without getting into it a bit. If I could set cruise control here I would, radar on this strip daily. Once out of town the hills and speeds increase, but require a heavy foot to downshift.

I will swap out the fluid for the fun of it and just use manual mode if I donít like the decision itís making for me. I know, thatís what I get for buying an automatic Jeep. Just not like my other car and truck pedal wise.

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