Chevrolet Repair: 1995 chevy van transmission wont shift, chevy van, couple suggestions

Question
This van sat in a yard for about six weeks.  It had been running just fine.  I started it up and it would not shift out of first gear.  I can start in first and manually shift to second but when I shift up to drive its just like putting it in neutral.  I can start out in drive and then down shift manually to second and it will go to second but it will not shift back up to drive.  Also the speedometer will not work.  Also it is dufficult to shift back into park after driving in second gear.  It takes a lot of manual strength to shift it back up.

Answer
Hi Robert .... I am not trans expert but i will make a couple suggestions....first check fluid level...HOT... if level ok disconnect linkadge at trans...check if stiff shift is at trans or in linkadge...if linkadge lube and free up...if trans you may have some condensation inside trans and has caused some parts to get some rust on them...drop trans pan drain fluid install new filter kit and refill adding some lucus trans conditioner...start and warm up then try road test....you could also take to trans shop and have it machine  flushed...it sounds like from sitting it has a control valve stuck inside....i know it's not much but i hope it this helps