Is it hard to change a TCM in a 2005 Durando SLT AWD WITH A 4.7 ltr?

Not a problem. Be sure to disconnect the negative battery cable first and also be sure to ground yourself. This will prevent static electricity from damaging the new module.

You will likely need to perform a relearn.
If you have a scan scan tool that will go quickly. If no scan tool is available, you will need to do a long or "drive" learn to fine tune shift adapts, etc.
Are there any fault codes?