I am trying to replace the hood cable release cable assembly on my 1985 244 but ran into a "situation". I have the 2 clamps in the engine bay off and according to the Haynes manual, I should be able to pull the assembly though the firewall from inside the car.

But when I tried pulling the plastic sleeve that is clamped to the firewall, it doesn't want to let go. I tried pulling on the plastic sleeve (that the release handle shaft is in) with vice grips but it won't come off and I hate to break something in the process. I realize there is a plastic clamp on the inside that holds the assembly to the firewall but I can't get to it with a tool such as vice grips as it is very cramped and crowded. Is there a trick or something I am missing?