FWIW, If you take a shopping cart and cut the basket off you can set the whole assembly on the cart and wheel it around. It's not up high enough to do detailing, but as a fabricator I'm sure you could extend it up where you can work on it.
The engine goes over the cart and the transmission just hangs off the rear of the cart. The upright left over goes between the torque convertor and the rear of the oil pan. I've used a 4X4 or c couple 2X4s to support the front of the oil pan. Because the casters on the rear of a shopping cart are way to the rear it balances the load just fine.
More than one shopping cart has given it's life to act as a engine/transmission dolly. I used to have a few modified carts to wheel engine/transmission complete assemblies around my garage.
This picture gives you the idea of caster placement and balance of the whole assembly easily movable to work on it. very similar to the shopping cart balance points.
That's a 4L60E hanging on the back of that LS engine, right around 140 lbs. approximately same as a T400, bolted to a much lighter engine than a Stratostreak V8 is. The key being is the majority of the weight is resting on the rear of the dolly to allow the balance point to be near the caster on the rear.