The torque converter will only slide out if tilted down, there's no pressure there. The filler tube may be difficult. It can be removed but the nut securing it is extremely tight. If all else fails, take a hacksaw & cut it off then wrestle with the nut to remove it & replace it with your old one once they're both on the ground in front of you. If you do that take a piece of paper towel or tissue & jam it down the tube with the dipstick so it's below the point where you're cutting it, to keep metal shavings out of your transmission. No speedo pickup on the transmission, it's on the differential cover. If your car uses a cable-driven speedo run from the tailshaft housing of the transmission, you can switch housings & swap the gear in place of the spacer that a newer tranny has. Takes about an extra 10 minutes & a new tailshaft housing gasket, and this is the time to replace the tailshaft seal & bushing - add about $30 to the cost of your repair to have some assurance that you won't need to mess with it again for a while.
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Chris, Dartmouth NS Canada 70 M-B 280SE, 83 245DL, 84 244 turbo, 90 780 turbo, 92 VW Golf, 90 740 Rex/Regina