Lftrn97 Posted December 30, 2015 Posted December 30, 2015 1989 Comanche Pioneer 4.0 automatic stopped shifting out of first so i pulled the TCM fuse and it shifts fine manually. Does this mean for sure that the TCM is bad?
gogmorgo Posted December 30, 2015 Posted December 30, 2015 Easiest way to find out is to swap it with a known good one. Best bet is one that matches your transmission's year. They don't go bad all that often, but that would make it seem to be a problem, yes.
HOrnbrod Posted December 30, 2015 Posted December 30, 2015 What this means is that the problem is most likely electrical, not mechanical since it shifts normally manually. Before trying another TCU, eliminate the obvious first. Look at the AW4 wiring harness and all connectors between the transmission and the TCU, especially the one on the firewall. The three AW4 internal solenoid(s) that control shifting from the TCU could also be bad. You can ohm them out at the firewall connector. This thread will be useful: http://comancheclub.com/topic/47262-does-not-shift-into-4th-gear/?hl=solenoid&do=findComment&comment=482315
cruiser54 Posted December 31, 2015 Posted December 31, 2015 Check the tCU fuse for continuity and do Tip 10 in my link below.
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