Transgo & 4R70W trans problem blinking O/D light

[Modmadness01]

2 weeks ago i bought a transgo shift kit for my 98 4.6 mustang gt w/aode/4r70w tranny, after i got done with the install i satarted the car and drove and i noticed the overdrive light was constantly blinking. So i took it to a tranny shop and they told me it needed re-building so thank God for a good warranty, after all is said and done the new tranny was put in and i still have the blinking light I double checked what the shop did including taking the pan back off and making sure everthing including the wire harnes connections were good and tight even where the male and female contacts are in the harnes. Ive also tried resetting the computer OBD II by taking off the battery connections on both +,,,-- ..started the car agian and the light stopped blinking so i drove around for a while and about 2 miles up the road it starts over agian ??????????? I'm clueless any help would be very appreciated. P.S it has no shift kit in it now and has a new valvebody

Greg