I installed my engine and transmission recently into my 69 firebird and got the engine up and running very smooth but now when I put the car in any gear it can take anywhere from 30 seconds to a minute to drop into gear.It is a turbo 350 but hasn't been run in over a year,although a year ago it had no problems shifting.I also should let you guys know I completly drained all the tranny fluid and let it sit without the fluid in that time span.I did put fresh fluid in it up to spec.Could the kickdown have anything to do with this.I hooked it to the throttle linkage but wasn't sure where it was supposed to be set at.(I believe it's the kickdown or maybe the detent cable.Anyway it connects to the carb linkage).Any help would be great.Ive been having problem after problem.So far you guy's have helped me fix every one of them.Thanks for all the info.
Was the car running when you refilled the tranny? In order to completely fill the trans and the converter, the car has to be running. Also, check the flud now while it's running to see that it is indeed full. Your symptoms are those of an under-filled tranny.
Try putting trans conditioner in your transmission.Because the trans sat for a year with no oil in it,the ball bearings in the valve body are probably stuck or the pump may be weak.
Ok I just got home from work,and started up the car.Right now I'm letting it warm up to check the tranny fluid level.The weird thing is the car is at idle and when I give it gas I can hear the fluid in the transmission swirling around from inside the car.I've never had this happen before is that normal?