What does it mean when.....?

Hello to al again. I am still troubleshooting my Burb's Tranny. What does it mean when I unplug the ecm/pcm and the tranny shifts fine for about 5 miles? I hve done this periodically and I fine that it shifts when disconnected over about a 1 hour period. Now although it does not do the trick ALL of time, but it works more than not. Now I have 1-2 shift mos of the time after I added some more Lucus Slip fix stuff.
And I still do not have any codes! I wish I did though!
Blessings
Chuck aka ulremember

What year and engine and mileage on transmission?
Has transmission ever been serviced?

Your transmission is going into fail safe mode because of a engine/transmission problem.
When you unplug the VCM/PCM it clears code and resets it.
Then when you drive it code trips and puts the transmission in fail safe/full line pressure /second gear mode.
You will have a code or code stored in the computer for the problem in history /or past/present codes.
Read them out with a good engine/transmission capable scanner and read out transmission shift data and operation.
Post back code no.or no's.
So we can help you.