Hey guys,
I had the same thing happen with my Trooper....it was electrical, but was the neutral switch on the side of the tranny that was causing the problem. Call an Isuzu dealer and ask about this.

110k! Have you had the trans. filter changed? My VX had the light come on. The code thrown was for "slippage". Turned out the filter was clogged. I changed that and filled it up with fresh fluid...no problems since. <img src="/forums/images/graemlins/kewl.gif" alt="" />

Although I can't prove it beyond a reasonable doubt there is some thruth to the electrical gremlin theory.

I had the same issue with my 95 Passport. The light would come on everytime I would pull a big hill. Clear the code and the light would go out only to come back on later.

I replaced the tranny at a total cost of roughly $2,500.00 used through Phoenix hardparts (don't go through them, long story but absolute nightmare). It took two days replacing the tranny. I also installed a hayden secondary tranny cooler, a big one, I don't remember which one but I definitely overkilled it. The first time I went offroad and placed the T-case in the 4x4 the tranny light came on. I didn't drive the vehicle much so I just blew it off, but on the occassion that I took it out it happended over and over. Finally the alternator punked out on me. I replaced it and wouldn't you know I can't get that tranny light to come back on anymore.

You can always buy an alternator, install it, see if that fixes the problem, if not take it back, or keep it as a trailspare.