If you're talking about the 3/4 ton one wiith the hex head ends on it, DO NOT use a impact wrench on it. The same goes for the bolt style internal coil spring compressors. The soft alloy that the threaded parts are made from (likely # 2 hardness chinesium) rolls the threads over when you use an impact wrench on either tool.
This does 2 things, it makes the threads eventually fail, and it makes them bind up. Idealy this should have an Acme machine thread screw, and nut to perform well The Acme thread has square threads, rather than the pointed conventional fastener thread..
So yes you should lube the threads, but if you already used a impact on it, likely they are destroyed.
Most every leveler sold on the internet looks the same as the HF one, except for the OTC brand. OTC has been known to make better quality specialty tools fo decades, so they sell from about $90 and up, depending upon who is selling them.
Link to OTC leveler:
https://www.amazon.com/OTC-Engine-Lo...89846611&psc=1
If all else fails a ratchet strap from the suspending chain to the rear of the engine will also work.
Myself, I quit pulling engines, and transmissions as a unit when I started wrenching for a living. Removing/installing each part seperately has a much better outcome that trying to wrestle both units into a chassis, especially when you're trying to do it with one man. It's much easier to get the mounts to align so you can get bolts in when the engine doesn't have all that unwieldly weight hanging off the rear.
FWIW, the 4L80E is about 50 lbs heavier than a T400 making the struggle even harder, and it fits into the transmission tunnel much tighter too.
They were installed as a unit at the factory, but the body was off of the chassis.