I got my rebuild kit for my 700r a few days ago. Along with that I got a new reverse drum from transmissioncenter.com anyhow, i noticed that the drum is for a 93. my tranny is a 91. the difference is that the hole between the bushings is square(93) vs 0.095" round(87-92). I called the guys at transcenter and told me i could put the drum into my 91. I am looking for a second, third, forth, opinion. it's my first 700r, and i don't want to do this twice. the atsg manual mentions that there are three different types, "that will not interchange". the 91 uses 2 checkballs vs 3 on the 93. the 91 does not accomodate for a 3rd checkball. anyone have previous experience doing this?? thanks in advance, ARQ.