Computer problems? Need help!!!

[rlm316]

I need some help! This question is about a 94 G20 van and I thought that I would post it here because alot of you guys are running the same engine setup in your trucks. Here we go. Last night on my way home from the last job the van would not shift out of 2nd gear and the speedo went to 0mph and stayed there and the abs light was lit in the dash. I pulled over into a gas station and shut the truck down for a few mins. When I started it everything seemed to return to normal. After a few miles all the same symptoms returned exept being locked into 2nd. I don't know if that is because it was up to speed and had already shifted into high gear. When I got back to the yard I disconnected the battery for about 10 min. I reconnected the battery and took it for a test drive, every thing seemed OK until I stepped on the brake. When I used the brakes for the first time slowing down from road speed, it seemed like the ABS was engaged and the speedo was acting sluggish and not giving me a true reading. This morning while on my way to work which is about 5mi. everything acted normal. I don't have too much experience with these computer issues so I could really use some help diagnosing this. Thanks in advance, Lane