tranny is going bad, i suspect this because when i accelerate in first gear and make the switch to second, if i let off the pedal or brake or decrease in speed at all, i get kicked out of second gear, burning my clutch..
a friend recommended to start looking for rebuilt trannys or seeing if someone can rebuild it..how much would rebuilding my transmission cost?

 

A lot. I'd try looking at the shift linkage and see if it needs adjustment. You may be able to do something about it. Hopefully Mike-2ptzero will chime in - he's a guru with these drivetrains.

 

redline MT-90 works well in these manuals, but yours sounds like more help may be needed. if you live near lebanon,pa APTuning does great tranny work, a rebuild with syncros and a new used 5th gear in an o2j 5spd cost $1200, install + removal excluded, couple days turnaround