The linkage is easy to switch. The used transmission should come with the bell housing. If you have the bell housing off, or change it, you should check the shim thickness for the countershaft. It should be fine, assuming that Volvo assembled it correctly and the replacement gasket is the same thickness as the original gasket. Whatever you do, don't loose the shim. When I get my regular computer repaired (I'm waiting for a warrantee repacement Soyo motherboard) I will be glad to scan and send you the information.

The drive flange can be tough to remove. Volvo used Locktight, or a similar product, on the overdrive output shaft drive splines. You may want to use a puller.