Here's a great product I picked up for under $100 at Harbor Freight. I've used it about a dozen times, this year and I still get a kick out of using it. I have yet to see it actually "work" to get a fastener loosened. It's more like "blip", and the nut or bolt is loose. I have nicknamed it "The Boss". So far it has been gentle enough to not break any fasteners upon removal. I use a low torque impact for putting them back on, or a torque wrench as needed. Taking off an overly tight variator or clutch is so easy. Just hold the part in your hand, "blip" it with The Boss and It's done. It weighs a lot, but The Boss, is the boss of nuts and bolts. Engine mounts? Blip! Wheels? Blip! Bolts so tight you think you might break them if you try to loosen them by hand? Blip! Grrr! Ugh! Ugh! Ugh!
Matching big impact socket set and adapters sold separately at surprisingly affordable prices.