The 1st & 2nd shift arm on my 1981 240d 4 speed was way loose and causing a lockup problem.  I tightened it with an allen wrench with what I thought was the neurtral position.  I undid all the bushings, put the pin through the gear shift in the neutral position but I cannot get it to run through the gears.  I assume I did not get the proper setting on the 1st and second arm.  Is there a way to make sure that I am in neutral on all the gears0?  Here's the other thing.  With the engine off it shifts beautifully.  Once the engine is on it does not.  I can get it into 3rd and 4th with some difficulty and reverse grinds and will not go in.  I have replaced the slave and master for the clutch and bled the system successfully.  It was only when I fooled with tightening the 1st & 2nd gear arm on the tranny did I find myself in trouble.  
