Auto trans not shifting

[Squamch]

I've got a beat old 4runner I use for hunting and exploring. 1992, 22re, auto.
Last weekend it stopped downshifting when I stopped. Had to manually shift 1-2-D. Everything else worked as well as can be expected from a 30 year old truck with over 500,000km on it.
Solenoids?

 

[Aisin]

Probably solenoids. If the pan is full of trash it’s time for a rebuild. You can test the solenoids with a multi meter and an air hose. It’s easy to test them.

 

[Squamch]

Probably solenoids. If the pan is full of trash it’s time for a rebuild. You can test the solenoids with a multi meter and an air hose. It’s easy to test them.

I just changed the pan gasket and filter, and dropped the trans to do a rear main.

 

[Aisin]

Test the solenoids. Not uncommon for A340s to go over 400,000+ miles provided they’ve been serviced regularly.

 

[NOODLES]

Check the kickdown cable too. They separate at the transmission side where the cable goes through when abused during trans r and r.

 

[Stingray]

I'll agree with Solenoids, another thing to test is the harness from the solenoids to the outer plug on the truck, There is a small $18 harness inside the trans hooking them together and passes through the trans. I had the same symptoms, replaced all three solenoids. Still had the issue, drove it almost a year manually shifting it, then I finally took a picture ( the connector faces upwards) so you cannot see it. when the solenoid smoked it burnt off the prong for the connector to that solenoid.
almost 300K on a SASed 3rd gen on 37's and it shifts perfect.

Regular fluid and filter changes help. generally a robust trans.

I also did an external magnetic filter before the cooler.

 

[Stingray]

This it the harness inside the trans, connecting the solenoids.