Diagnosing over the phone is tricky.

Are you absolutely sure it is "slipping"? If so, there is no cure on this planet other than a re-do.

However, if it is merely 'stuck in 2nd gear (limp mode), then that is another story entirely.

There is a solenoid A and there is a solenoid B. The combination of these two solenoids (their respective on/off status) is what determines the gear. And yes, they live in oil and are saturated all the time.

Okay, this is why I preach, "know what is wrong before you ever pick up a wrench". Any other approach is just chasing rabbits and guessing.

Your code is saying that the computer is seeing an error (not going into 3rd). He!!, we already knew that. :>)

Since you already have this guy apart, here's what I would do:

Take that filter, put it in a vise clamped at one edge. Break the filter open, unfold the paper and tell us what is inside that thing. Look for rubber, clutch material and/or metal. Was there any BLACK mud in the bottom of the pan? HOW DOES REVERSE ACT?

Hollar back and we'll get to the bottom of this rascal.

Allan