hard shifting 833

I tried ATF in A833 tranny, was not a good deal...(drag racing)...I seized rear bearing to the shaft so bad that a 20 ton press and a torch could not get it loose....I called Bloominthal tranny and Liberty transmission and they said regardless of recomendations never use ATF...The clearances in these trannys were to great...They recomended the Mystik I believe it is JT6...The red 80-90 or 85-140 (would have to look)...I put this in and my tranny, it shifted great and never had another problem...I hope this info will help...Lee