Cadillac: Rough gear change from 1st to 2nd, cadillac deville concours, cadillac deville

Question
I have a 1995 Cadillac Deville Concours, and there are days when it seems that on take off, the transmission is in low gear, then at about 18 mph, it shifts really hard into 2nd gear.  From there on, it's OK.  This problem is intermittent - if it happens once, it happens all day, but the next day, it might be fine.  We've had the transmission screen changed, as it felt as though the screen might be plugged, and this helped for about 6 months, then it started happening again.  Our shop says the screen is not the problem.  What else can it be?

Answer
The first thing would be a road test by myself or a transmission tech and next would be a pressure test on the transmission.

It could be an intermittent sticking valve in the valve body or several other possibilities. There is just no way for me to tell you what the problem could be without performing a road and pressure test FIRST.