Ex in default of mortgage I hold

I live in New Jersey. My ex and I worked out a buyout deal in which I signed over ownership to him and obtained a mortgage on the property for the balance of payment. It was to be a balloon payment and he is now in default by almost a year and is also in default by not keeping the property in good repair and a few other stipulations. The mortgage gives me several options in the event of default, one of which is to take possession of and manage the property. Since I am already residing on the property can I just give him a notice that I am assuming possesion or do I have to get a court order?

[HomeGuru]

Your post is confusing. Why would you sign over the property to him and be responsible for the mortgage?

Sorry, I guess I did not make myself clear. I am the mortgage holder (lender) on the property I signed over to him, he is the borrower. He gave me a downpayment on the buyout agreement amount and the mortgage is for the balance he owes me.

[HomeGuru]

You need to read your mortgage document as to your remedies. Generally, you must give him a demand notice of default and to cure by a certain date. Then if no action by him, file court action to foreclose on the property.