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We have this Jeep at Rpmextreme. Our conversion harness does have the inputs for the parking brake switch and all the different brake switch inputs so a relearn will run and complete. Opening the door doesn't make a difference and I don't think its needed in a swap application thats not using a GM BCM.
His T87A will not allow the vehicle to move or shift into any gear, it just free revs. the PRNDL display on the dash does not change when shifting thru the gears. I did a Trans relearn and it will run the test and you can feel the transmission going into the different gears and pulling. Once the test was complete we still didn't have any movement.
I installed a T87 that I had laying around and the PRNDL started working and the transmission will shift and drive. Im not sure what solenoid pack the TCM was programed to, it does shift thru the gears but not great. 5th gear will flare real bad and usually will not engage but 6-7-8 will. At this point I'm not sure if it has a transmission issue (it was rebuilt) or if I need to try and flash the TCM with matching solenoid info.
I there a way to look up and see what TUN the TCM is programed for?
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HPTuners equipment can read the OS from the T87. Then you should be able to look up that OS and see what rigs it is calibrated for, gear ratio etc. Since it has a T87 in it now, you can do a full read and tune it how you want. Of course it is preferable to write the solenoid info to it (when you happen to have a 2015.5 or 2016 8 speed rig to use for the process) but for now at least you can tune around it.
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There are two different prndl set ups for these trans. One is a four pin and one is a ten pin. I always have to check the data list to see which one it has before I order a new one from parts at my dealership. This may be why the one worked and the other did not.
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Did you end up figuring out a solution to this? I have the same issue with a swap I'm doing and I've tried the suggestions in this post multiple times and nothing. Wanted to see if you figured it out.
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Has anyone had a similar issue and fixed it?
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Yes we took a T87 and had it programed with the correct TUN data and it works fine. What I am seeing is even though you buy a "pullout" and they say that the ECU and TCM were from the same vehicle, that is not always the case.
I just had a customer that purchased a 2019 6.2 10L90 with matching ECU-TCM. Once he read the ECU it came back as a 2017.
These 8L90 10L90 are a pain in the butt if you don't get the matching TCM with them.
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So the T87 worked on the 2018 l86/8l90 setup?
