Dying monkey-puzzle tree

My 10-year-old monkey tree trunk is oozing sap and some of the branches are turning brown and dieing. The tree has a split trunk only the one on the left is oozing sap and has dying lower branches the other trunk does not. Water usage has not changed. Can I cut off diseased L side to save R side? Desperate to save it or keep from invading trunk #2!!

 

Can you post some pics? Might help to understand the situation better.

 

Here are 4 pics. Thank you!

 

There are two possibilities, either to prune only the dying/dead branches or to cut down the entire affected trunk.
It is difficult to make the decision, though, without knowing the cause of the problem. May be someone on this forum will come with the idea what could be causing this excessive sap production.

I would be a little apprehensive of cutting the whole trunk, since this have potential to affect adversely the other, healthy trunk, too. Pruning only the dead branches is risk free and I would do it first.

 

I will give it a few more days, hopefully I will hear from someone else.

 

Any updates?

 

I am not an expert on monkey puzzle trees but I grow a lot of Abies. If that were my tree I would cut out the second trunk at the base and hope for the best. It is a tree best known for its symmetry and the second trunk ruins its best feature.