904 Transmission Stopped Going Into Gear

Thanks for the reply's everyone!

Im new to the strange world of automatic transmissions, so I'm doing a lot of reading on all this, bear with me.

From what you both said, does this sound like the correct sequence of steps to take here, in order of increasing effort?


1. Pressure tests starting with L/R servo as @AJ/FormS suggested because I can get reverse sometimes. Test all ports if that looks good. Should I just get an "oil and trans pressure tester kit" from the parts store like this?
upload_2018-4-18_9-25-0.png

Anyone know the fitting thread size on the trans? Does someone have a write up for this procedure? This is what "the book" has:

upload_2018-4-18_9-16-30.png

upload_2018-4-18_9-16-49.png

2. Drop trans oil pan, drain fluid, inspect, change filter and adjust bands as @Tooljunkie recommended. Also drain torque converter. Maybe throw some "magic" AT-205 in because why not. Test trans.

3. Contemplate dropping trans and rebuilding.


Does this plan sound good? For what it's worth, this is what "the book" says for this situation:

upload_2018-4-18_9-12-29.png