2001 LC, had since 2012 - first owners were my in-laws. The ECT Normal mode was always sufficient except for hauling. More often in the last few years I have been putting it in ECT Power mode just to drive around. Today I looked at why the truck feels "wrong" in Normal mode and I noticed that the computer is dragging the RPMs out and massively delaying she gear shifts in normal mode. It makes the motor loud and slow - much slower than it should be. If I turn on ECT Power the shift points are at RPMs that are 1/2 to 2/3 of what the NORMAL mode shift points are (ECT Power shifts are "supposed" to be later and higher RPM than normal, not the other way around). Also in Power mode the shifts are basically instantaneous as compared to Normal mode where the computer has resolved to drag out the RPMs and "HOLD" them there for a second before slowly switching gears.
Even if im very light on the throttle, the computer still drags out and delays the shift point. It 100% stops doing this in ECT Power mode, shifts normally and the engine sounds normal.
Ive driven this truck since it was basically new. The trans is operating very poorly in normal mode. However I dont think this can be a physical maintenance issue as simply turning on ECT Power mode makes the trans work perfectly "normal" again.
WTH could be happening? I do partial transmission changes every about 40k miles and always have, but I dont think that's the issue because the ECT mapping makes the problem disappear immediately.
Even if im very light on the throttle, the computer still drags out and delays the shift point. It 100% stops doing this in ECT Power mode, shifts normally and the engine sounds normal.
Ive driven this truck since it was basically new. The trans is operating very poorly in normal mode. However I dont think this can be a physical maintenance issue as simply turning on ECT Power mode makes the trans work perfectly "normal" again.
WTH could be happening? I do partial transmission changes every about 40k miles and always have, but I dont think that's the issue because the ECT mapping makes the problem disappear immediately.
