When I had the trans rebuilt I did use a heavy duty red band... The valve body is original with a transgo shift kit and the trans always would freewheel in 1st gear, even before the rebuild so that must be how it works.......
I did not get a chance to pull the trans yet and it will have to wait until the weekend. I wanted to take this car up to the garlits show next week but I am glad the trans broke close to home...... Keep munchin the popcorn as I will have the autopsy results soon...... TBF