3rd.. Gear Blues

[RUQWKNF27]

My car has a 26-2800 stall in it. Shift good an hard from 1st to 2nd.. has only 75k on it. But my problem is that it revs forever before going into 4th gear, even to the point that I have to let off the gas , just so it will shift into 4th. Could my problem lie in the T>V> adjustment cable on the Throttle Body. Could the previous owned adjusted it so tight, in order to shift hard that it is messing up the 3rd to 4th gear change. but doing good on the 1st to 2nd gear change???????????????????????? An i'm not sure if this is anything but or maybe just my imagination but sometimes it seems as if something is grinding , it might be that my dope in the rear needs to be change. Or that the motor is reving so hi in 3rd gear that the tranny is getting to much pressure??? can anyone help. No other problems than this... SO FAR!!!!!