92 Loyale m41 auto

My 92 Loyale has a shifting problem with the 3 speed automatic.

I pulled the governor and all appears well, it moves freely, and the gear is in good shape.

It shifts into reverse fine, and low fine. Will shift to second fine, but takes a while to shift to third. When it does shift to third it is solid, (no slipping). But the second you let up on the accelarator pedal, then step back down it is back to second gear. It does brake the car in third when slowing down, but jumps back to second when the accelarator is pressed down. After a few minutes, all of a sudden it will shift into high and here you go. I can't get a book for this transmission locally, and can find no pictures of the valve body to see what valves may be sticking.

What symptoms would this transmision have if the modulator valve is bad?

The fluid is pretty red and doesn't appear burnt, and no silver flakes can be seen in it. Appears to be a valve body problem, but hate to tear into it without a diagram of what goes where.

Thanks

Roy

Can anyone tell me where I can get a book on the M41 3 speed? Or at least a picture of the valve body parts and where they go. Still think I have a valve body problem, but not sure who to ask. Help