r90/6 transmission gear removal

[dwmxr]

I'm O/H'ing the tranny. Flange and cover are off, main shaft removed. Need to remove the remaining two shaft/gear clusters. The dang things will not budge. I've heated up the box, nothing. I've heated the box and tried a slide hammer, nothing. I've filled the box with dry ice to super cool the shafts and then heated outside the box at the bearing boss and then used the slide hammer, nothing. The large bearing on the output shaft hasn't even moved. Am I doing something wrong or did der kraftsmen in Berlin put this one together really well back in 1976? I'd appreciate any experienced suggestions. thank you. Brian