astonshing. in sum way ur like me man u dish $ out in anything u can to fix a prob, funny think is it runs like a charm huh.
my god no comp no error code, id go str8 to the tranny now.
although if u did fix the tranny and it still did this id be really pissed, go for it i can tell u this if u get 1st n 2nd gear to les than 1100 rpm from what my tac says the car will shudder madly.
have u played with the carb any?
i would grab a compression tester and see if the engines worth a new tranny before i threw the $ out.
see what kind of a deal u can get http://www.mantrans.com/trans.htm
i bet u can get a stick in there including a used shifter assembly from a junkyard and a new higer than oem quality tranny for less than it would be to fix that automatic.
otherwise buy a rebuild kit from say www.jcwitney.com
or maybe www.summitracing.com
go to checker autoparts and have them pricematch it. if u dont got a checker near u then order it and take the kit and trany to a half decent shop and hand it to them and dish out maybe 3 or 4 houirs worth of work lkabor rate.
or pay big buks have them jack the actual cost of the tranny rebuild kit, and have them take it off and put it back on and fill it. i guess it kinda depends on your situation but do consider this man and do not buy a autozone tranny!!