Same- I just pulled a Certified Calibration 140 out of a ATX Taurus GL (go figure- must have been a cop shop cruiser) today and put it into my MTX. There is a white clip with a small 1/4" lip inside the clip that rides around the cutout on the end of the speedo shaft. I heard horror stories about getting them out, so I passed it up Saturday, and decided today that I wanted it, since I was going to the pick 'n pull to grab something for Calypso, too- meaning I had time to take the cable apart, yada, yada, yada.
So, I pulled the bezel, pulled the clear cover, pulled the black trim inside the cluster, and pulled out the fuel and temp gauges (they have pins for the connectors- they pull right out just like our tach and fuel/temp gauges- no wires. The ATX has a small PRND21 window on the bottom that is blacked out on the MTX, (which is where our pesky low coolant light is) and the two hex screws that hold on the speedo on the bottom also hold this this in front of it. If you take those out, you can pull the speedo and leave the rest behind, since you should have your MTX peice, or you can easily add your ATX peice if you have an MTX speedo to put into an ATX car.
Anyway, when I pulled the speedo, I had enough cable slack to be able to pull the cluster out about 6-8" (same as my car) and I stuck a long screwdriver inside the connector (between the speedo shaft and the white connector from the front of the cluster, and gently pried it away from the shaft, wiggled it, tried another spot on the connector, wiggled it again, (must have been right on the little pin) and it popped right off. What was the big deal? Did I just get lucky? It took me 5 minutes, and no grief at all.
Just be sure not to pry too hard- they're old brittle connectors, and they will probably break really easily with too much force!
