I'm trying to see if a valve body out of a later trans with part-throttle kickdown is in decent shape. I can't get the 2-3 shift valve to pass through the final orifice in the valve body - it gets too tight to push through as it starts becoming flush to the outside.

The whole VB is a bit clutch-dusty, but hitting the area with brake cleaner and then some new ATF didn't seem to help. I'm wary of using much force or direct heat for fear of messing up the whole casting. Do I need to clean up the orifice at the edge of the valve body more? Heat up the whole thing in the oven or something? I can't figure it out.