I recently acquired a '93 940 and am having a tranny issue.

The car will shift by itself from 1st to 2nd, a little rough, a little on the jerky side.
It will not shift into 3rd or 4th at all when driven normally (at least up to 3500 or 4000 rpm, but I'm hesitant to rev it higher), but will shift very nicely if I let my foot off the gas.
Downshifting seems to be completely normal.
The throttle cable appears okay. The transmission fluid is at the proper level and doesn't appear to be burnt or contaminated.

My sense is that the transmission is probably okay and that something else is causing it not to shift properly.
Do you think replacing the speedometer head would be a good place to start?
http://www.brickboard.com/RWD/index.htm?id=1353565&show_all=1
I'm pretty much going to have to go at with trial and error as I don't have any testing equipment and am at the basic backyard mechanic level.

Thanks in advance for your help, and Happy Thanksgiving.

Dan