Thank you for your reply, definitely would not use a heat gun, I used a hair dryer, to no effect, I did try the Aerokroil, keeping the unit face down so it would not drip into the unit, that also let the Aerokroil follow the threads, still not effect. There are no signs it was glued, but it acts like it was. I think next I'm going to use a hole saw in wood that will let me set the body through, then drill holes in the wood to put screws through the mounting holes in the unit, then make other holes near the squared off part of the body in the wood and put pegs around the body at support points, so that when I put a strap wrench on the bezel the twisting force isn't entirely on the units mounting points.