Resetting Transmission shift points

[RIVICON]

Greetings fellow Jeepers. I just wanted to share my experience with transmission shift points and larger tires. I'm sure alot of yall are having this problem with hanging shifts or losing 8th gear after going with larger tires. My wife's 2020 JLUR has been lifted 2.5" with 35's. I recalibrated the speedo using the Jscan app and bypass cable with a Vlinker MC+ bluetooth OBD adapter. We recently made a roundtrip to PA from Florida and the speedo and GPS were dead on, however, I noticed the shift points were off. I seemed to have lost 8th gear on the highway and sometimes it would hang in 6th or 7th gear on a flat road. I'd either have to let off the throttle a little or do it manually to get into the next gear. It seemed to be a chore instead of a road trip. Well yesterday I was tooling around in Jscan and saw a TCM module(Transmission Control) and found an option to reset shift adaptations so I reset it and went for a test drive on the highway and lo and behold I got my 8th gear back. Not only that but it shifts way better and doesnt hunt for gears. I'm assuming the adaptation that was in there was learned for the factory 32" tires and now it's relearning for the 35" tires. I've heard of some people going to the dealership to get a reprogram and I think all they are doing is resetting the TCM adaptations so save your hard earned money and try out this method and see if it works for you ?

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[Rhinebeck01]

@RIVICON

With a programmer, you set tire size. After you set tire size, your automatic tranny JL/JT, does the rest in regard to the setting shift of points.

This process.... of shift points being re-established after you correct speedo takes some driving/mileage accumulation.

Also, you may or may not see 8th gear come and go so to speak. It may go AOL all together or you may see it come and go so to speak.

 

[RIVICON]

@RIVICON

With a programmer, you set tire size. After you set tire size, your automatic tranny JL/JT, does the rest in regard to the setting shift of points.

This process.... of shift points being re-established after you correct speedo takes some driving/mileage accumulation.

Also, you may or may not see 8th gear come and go so to speak. It may go AOL all together or you may see it come and go so to speak.

Correct, I set the tire size before we drove 2000 miles round trip to PA and back and for some reason I still got the erratic/hanging shifts even after we returned. Yesterday after I reset the TCM adaptations it shifted way better and 8th gear returned on highway driving. I'm guessing it will shift better and better the more miles I put on it with the 35's.

 

[WranglerMan]

@RIVICON i have never reset mine and also run 35’s and have a corrected tire size using JSCAN and I occasionally see 8th gear but not a lot but like I said I have 35’s plus a steel ROAM front bumper and RC 9500 winch so my 3.6 grunts alittle and stays in 7th gear most of the time but do see 8th occasionally

 

[RIVICON]

@RIVICON i have never reset mine and also run 35’s and have a corrected tire size using JSCAN and I occasionally see 8th gear but not a lot but like I said I have 35’s plus a steel ROAM front bumper and RC 9500 winch so my 3.6 grunts alittle and stays in 7th gear most of the time but do see 8th occasionally

I also have the winch and the steel 3 pc bumper and heavy kmc beadlocks and I figured that was just something I had to deal with. Now it drives way better.

 

[Rhinebeck01]

I also have the winch and the steel 3 pc bumper and heavy kmc beadlocks and I figured that was just something I had to deal with. Now it drives way better.

@RIVICON

Whatever you want to think... Guess you assume the guys here that have been running the Tazer JL for almost 3 years and also fooling with JSCAN are clueless... 8-)

Many of us long time users know you are singing off tune so to speak.

Hopefully other's reading this thread realize you are singing off tune and don't take to heart what you are saying.

 

[RIVICON]

@RIVICON

Whatever you want to think... Guess you assume the guys here that have been running the Tazer JL for almost 3 years and also fooling with JSCAN are clueless... 8-)

Many of us long time users know you are singing off tune so to speak.

Hopefully other's reading this thread realize you are singing off tune and don't take to heart what you are saying.

Dude who the hell pissed in your coffee? Do you need a hug?

 

[WranglerMan]

@RIVICON the JL is technically supposed to relearn shift points after doing tire size changes but that’s in a perfect world and like other things with the JL things sometimes get jammed up and it’s VERY POSSIBLE the TCM did not relearn until you forced it to reset.

I’m pretty sure the engineers that built and designed the JL are ones that could give solid answers on this but all we have here is trial and error so if after resetting with JSCAN you noticed and felt a difference then there was an obvious issue and it’s good to know this.

My plan is to use JSCAN to do the same to see if I can gain more use from 8th gear as resetting the TCM thru JSCAN hurts nothing other than it relearning the points, to me I consider this as the same thing as restarting the ECU using the Tazer or JSCAN as all you are doing is forcing the JL to look at things again to make the changes work.

Case in point and it has nothing to do with the TCM, I had that pissy baby battery removed from my JL along with the main crank battery as I just hated where the ESS battery was and also wanted the extra boost and even though I only replaced batteries my JL runs so much better electrically as with the original setup it did start and run and never left me stranded but there were some annoying gremlins but after going to my new system they all went away so just because it works sometimes it only works better if we go a different route than designed and apparently your method worked so good for you.

Here is an excerpt from the manual but like I said this is in perfect world and we know from reading all the posts that the JL does have issues that sometimes needs to be corrected outside of it correcting itself and it needs a polite push like you did

 

[RIVICON]

@RIVICON the JL is technically supposed to relearn shift points after doing tire size changes but that’s in a perfect world and like other things with the JL things sometimes get jammed up and it’s VERY POSSIBLE the TCM did not relearn until you forced it to reset.

I’m pretty sure the engineers that built and designed the JL are ones that could give solid answers on this but all we have here is trial and error so if after resetting with JSCAN you noticed and felt a difference then there was an obvious issue and it’s good to know this.

My plan is to use JSCAN to do the same to see if I can gain more use from 8th gear as resetting the TCM thru JSCAN hurts nothing other than it relearning the points, to me I consider this as the same thing as restarting the ECU using the Tazer or JSCAN as all you are doing is forcing the JL to look at things again to make the changes work.

Case in point and it has nothing to do with the TCM, I had that pissy baby battery removed from my JL along with the main crank battery as I just hated where the ESS battery was and also wanted the extra boost and even though I only replaced batteries my JL runs so much better electrically as with the original setup it did start and run and never left me stranded but there were some annoying gremlins but after going to my new system they all went away so just because it works sometimes it only works better if we go a different route than designed and apparently your method worked so good for you.

Here is an excerpt from the manual but like I said this is in perfect world and we know from reading all the posts that the JL does have issues that sometimes needs to be corrected outside of it correcting itself and it needs a polite push like you did

That's great info right there. This will definitely help alot of people on here running into this problem

 

[WranglerMan]

That's great info right there. This will definitely help alot of people on here running into this problem

Thanks for posting your finding, I need to find time to do the same as you to see if I can carry that 8th gear more, I know it only takes a few minutes to do but with my schedule and my long list it may be a week or so before I get to it.

Honestly need to just but a SGW bypass module from Joe at Zauto as this would really make things simple but hard to justify the cost when I’m not in the programmer that much.

 

[RIVICON]

Thanks for posting your finding, I need to find time to do the same as you to see if I can carry that 8th gear more, I know it only takes a few minutes to do but with my schedule and my long list it may be a week or so before I get to it.

Honestly need to just but a SGW bypass module from Joe at Zauto as this would really make things simple but hard to justify the cost when I’m not in the programmer that much.

It would be more convenient with the bypass module. Saves from having to pop the dash cover off and tie yourself in a knot to get the plugs off the SGW everytime. Not easy to do with my Wreck-It-Ralph hands.

 

[21SargeJLUR]

Calibrated with JSCAN yesterday. I had to play with sizes some to get it on speed. 34.5" was +1MPH 34" was -1MPH and 34.25 was spot on... Taking a longer road trip this weekend so i'll see about highway shift points.. just testing some yesterday briefly and my short drive to work seems pretty normal.
In my JK (Sport with crap gears), when i calibrated for 35's it crushed the shift points and was sluggish. i ended up calibrating for 31-32" tires on it and dealt with the speedo diff just to drive normal.. JL much better.

 

[DavidArmen]

How awesome you got eight gear back! Resetting the transmission control module isn’t possible with the tazer is it?

 

[RIVICON]

Calibrated with JSCAN yesterday. I had to play with sizes some to get it on speed. 34.5" was +1MPH 34" was -1MPH and 34.25 was spot on... Taking a longer road trip this weekend so i'll see about highway shift points.. just testing some yesterday briefly and my short drive to work seems pretty normal.
In my JK (Sport with crap gears), when i calibrated for 35's it crushed the shift points and was sluggish. i ended up calibrating for 31-32" tires on it and dealt with the speedo diff just to drive normal.. JL much better.

The TCM reset option is a little tricky to find in JSCAN but you can find it if you go into adaptions>vehicle maintenance. At the bottom of the list is the TCM reset. You'll get a message about "transmission overhaul" and just click passed that and let it do it's thing then reset all ecu's when it's done.

 

[RIVICON]

How awesome you got eight gear back! Resetting the transmission control module isn’t possible with the tazer is it?

According to Zautomotive the procedure for M6 transmission is located here https://www.zautomotive.com/zpu/instructions/jlm6relearn.pdf Not sure how to do it with auto 8 spd though. Might have to contact Zauto to see if it's possible. I browsed through the user guide and didn't find anything https://www.zautomotive.com/zpu/instructions/TazerJLMiniUserGuide1123.pdf

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