4 Speed Automatic downshift issue 3rd-2nd

I have a 2007 Mazda5 with the 4SP Auto with Manual shifter.

I noticed lately when climbing a steep hill the 3rd to 2nd downshifts are delayed. When the engine bogs down and needs more torque, it won't downshift when it should. When it finally does, it does it with a hard sudden shift.

I can work my way up the hill by moving it into manual mode when I think it should downshift, and then lift the throttle a bit to ease up, and click it into 2nd.

It seems to be an rpm only based downshift problem. I tested by slowing down from coasting. The gear indication light shows 4, then 3, but stays in 3 all the way till almost a stop, and then shows 1.

If I am coasting and step on the gas, I can get it to downshift from 4th to 3rd, and again from 3rd to 2nd with throttle blips with no problems. Also it is smooth. So the throttle position or kickdown switch does seem to work as it should and the actual shifting is nice and smooth. Manual mode is also very smooth and works very well.

There is no dash light indicating an error code. Can a transmission code be read if there is no light?

As a search around, I see reference to the shifting solenoids, but not exactly for this problem. Some similar shifting problems, but no one has mentioned this exact one.

I had the fluid changed, which smoothed out the shifts all around, but did not solve it. The shifts were not bad before the fluid change, just much better after, which is to be expected. But it did not help the 3rd to 2nd gear issue.

So what component would cause it to not downshift into 2nd when it needs to by rpm, but will work just fine with a blip of the throttle, or in manual mode?

Interested to hear if this has happened to anyone, or some ideas.

Thanks,
 
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