@Furio

Agreed. Did Paul think Roy DeMeo would 'rat' over the car theft ring?

Or were their other problems that Castellano had with Roy?

Castellano was angry over him selling and possibly using drugs, plus killing people in unsanctioned hits. Castellano also wanted Gotti crew member Angelo Ruggerio dead for drugs, the Dellacroce tape recording with John Gotti clearly show that. Gotti would not give up his friend, and Dellacroce says in frustration that if the tapes are not turned over "We roll it up and go to war" So both Gotti (Or his crew member) and Ray were going to be killed. I think Castellano was a couple of decades too late, things had changed, and he had gotten out of touch with what was going on in the streets.