Originally Posted by Billybob

Use a second jack to support the front and keep it level, them lower the main jack an inch or two, then you can use the pry tool to lever the rear mounts. With the front hanging down it exerts off axis leverage on the rear mounts and the tubular studs they mount onto making it harder for them to disengage. Sometimes they will be stuck on there pretty firmly you just need to keep trying. A spray of KROIL to the top of the mount so that it can get on and leech down the stud can probably help some, and if you can get the tip of a bar, large screw driver, chisel in between the chassis and the mount where you can make some contact with its tip to the mount's inner/upper/central metal section into which the stub fits, giving it a "short, sharp, shot" or two, such a shock will help break it loose. The metal in the mounts are some alloy that can corrode and stick to the tubular stud's steel. This is the kind of stuff what "real wrenching" is all about! Good Luck!