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I'm starting to troubleshoot some shift issues I've been having and noticed that the Trans Shift Mode is always 4WD. How is this determined by the PCM/TCM? My initial thought was the Transfer Case Switch but it reads correctly.
The 4WD mode explains why I'm having issues with it not always downshifting to 1st when I come to a stop so I think its a good place to start troubleshooting. Log from this morning attached.
Here's a new read of the tune as well. I really don't see anywhere for the mode to be set to 4WD, though I have seen it on other vehicles
I haven't seen a 5 speed JK yet that didn't say 4WD in trans shift mode. What size tire and gear ratio are you running?
Yeah, that's kind of what I have been gathering the more I look into it. What I still can't figure out is how the PCM and TCM know to change shift behavior in 4Lo. Can't seem to find a PID that changes when it is put into 4Lo but I am almost positive that the shift behavior was different in 4Lo previously where it wouldn't downshift to 1st, you had to switch to autostick and put it in 1st manually.Quote:
Originally Posted by Mag0842
5.38's, 40's, Edelbrock SC.Quote:
Originally Posted by Mag0842
Had lots of help from @Hemituna as well as my local dyno tuner/friend to get it running as good as it does. I suspect I may have an issue with a valve body or something that is causing it to not downshift to 1st all of the time.