04 allison won't shift under WOT

[alumcj]

My tranny just started this. 60k on odometer.

It will not shift (up) under WOT. Sucks to floor it on an entrance ramp, hang at 40 mph, then let off and launch...weird!

[DmaxMaverick]

Welcome to the forums!

When was the last external filter change? Service history?

[alumcj]

i think its actually an engine issue. at WOT it seems to have no power....gonna start with a fuel filter

[DmaxMaverick]

Good call. You could luck out. Still, if it's been a while (or never), wouldn't hurt to change the tranny filter.

[Marvin Pace]

Just hade my 2003 in for the same thing, engine had no power, tranny would not shift up, no power,long story short, they change the fuel filter. Truck is fine now.

[rat4go]

Somewhere I read that the trans computer uses engine speed (when at WOT) to determine shift points. If something's keeping you from getting to the 3100RPM or whatever the shift speed is (fuel filter as was mentioned?), you wouldn't get the WOT shift as you'd never get to the engine speed. Maybe lifting off of WOT would get you back to where the shifts are based on vehicle speed and not engine speed, and thus you may get the upshift?

[Albee]

OK......this may be the dumb question of the month, but , what is "WOT" Thanks in advance. smile.gif

[MikeyB]

WOT= "Wide Open Throttle"

HTH

Mike