727 wierdness

So the 727 in the Duster is being flaky... fire it up..take off down the street 1,2,3...all gears. Drive it for 5 minutes and it doesnt want to go in to 3rd. I have set and reset the kickdown 20 times...this trans was rebuilt by me about 15 years ago but has really not seen any action until recently. I have not pulled the pan yet but plan to over the winter to see if when I put the shift kit in that maybe I didnt set the pressure valve correctly. Any other thoughts??
Author: admin