1999 Isuzu Amigo, 4wd.

Streetglideok is correct about the location of the sensor. I read the repair manual again, and the procedure seems a little easier than I thought the first time around.

I think it is like $85 to replace it, and everyone seems to have great results with just cleaning it out.

I was lead to this diagnosis by checking out an Isuzu forum and reading a ton of threads about the specific symptoms and the issue. Basically, when the transmission is cold, the shift from 2nd to 3rd, and 3rd to 2nd, is very rough. The accompanying symptom that lets me know I'm on the right track is that if I bring the car to a stop, and shift down through 3, 2, and L, the light on the dash does not correspond correctly with what gear I've actually shifted into.

Thank you for checking this thread.