Exactly how the subject says. It won't shift past first gear. It will start up and run pretty good, but just refuses to shift out of first. My dad and brother, as well as a few other people, have said it's most likely a problem with the transmission, yet somebody else said it could be a bad connection somewhere. We just can't figure it out, and we're looking to buy a new tranny for it, but apparently a tranny for a 91' euro is hard to find. If anybody can let me know what the problem probably is and how I can fix it, I would greatly appreciate it.

reminds me of a lyric in that Sammy Hagar song "I can't drive 55"

ok..try this...Shift all the way down to L1, get up to speed and then move the shifter to L2 or D.

Not the same problem, but I used to have a Olds Van. I had to shift to L1 to get the van to go into any gear (forward or reverse). But that was a low temperature (35F and below) phenomenon. Something to do with fluid viscosity and clutch plate wear, IIRC.

Might try here for a used tranny
http://www.car-part.com

There is a large vacuum line that comes off the back (driver's side) of the motor on top, and goes down to the tranny down low, facing the radiator.

The part it is hooked to is the vacuum modulator that tells the valve body when an upshift is called for. If the line leaks, or the diaphragm in the unit splits, it won't upshift.

Check the rubber at both ends of the line, and pull the line off at the tranny end and see if there is any fluid in it. If there is, you have to replace the modulator. It's easy to do, just has a holdown clamp like a distributor.