47re issue

[12vcumminsnc]

Ok tranny has a heavy duty(stock replacement) converter and a transgo kit. The problem is that it has started to pull and release at idle like pump looses prime. Itll pull for 2-3 seconds then release for bout same time. If the raise rpm to a hair over 1k it goes away. Tranny pulls and shifts fine otherwise. I have searched all over for a similar isses with no luck
thx in advance
Robert