Opening tender sound value 2-6-0

[Mixed Train]

Having trouble removing the tender body from the chassis on a sound value 2-6-0. I removed the two screws that hold the wiring harness at the front of the chassis but it seems to require too much strength to lift the front of the tender upwards so as to dis
engage the tabs at the rear. I'd like to install a keep alive.  I could attach photos if I knew how to do it! Many thanks, rich