Six speed bell housing switch

The truck belongs to my son and the throw out bearing locked up and destroyed the “quill” which is integral to the bell housing. We’ve sourced a used transmission and need to switch out the bell housing. Can I get some advise on the procedure to remove the bell housing from the transmission? We have all the bolts out and we’ve removed the plug and disengaged the snap ring for the countershaft. The part won’t come off. What are we missing?

 

You've probably found this already, but tons of info on this tranny here:

Transmission R-A60 manual transmission information . Your 6 speed transmissiom (WRITE UP ) | Tacoma World