Transmissions are very complicated these days and either no one knows how to rebuild them correctly or the repair cost is higher than a factory rebuilt one. That’s why Scotty does not recommend rebuilding it. 

Probably a new car that is still under warranty. But if it breaks that soon then you should probably get rid of it.

Under normal circumstances, by the time your transmission (it's pretty much the same for an engine) breaks, your car is probably high mileage and old, and just the cost of the transmission/engine itself is gonna cost more than half of the vehicle's worth at best. And let's say you do buy a brand new factory transmission, it's not like your car is suddently new, everything else is old and on it's way out.

In other terms, very rare are the cases where it's worth it, especially with a normal car. Most of the time it's more profitable to just get another car.

Depends on age/mileage and the overall condition of the vehicle overall. If you have spend a lot of time and money. If the transmission rebuild or replacement cost is worth more or as much as the vehicle or very close to the retail value of the car then I would say it isnt a great investment

Scotty says, and I've heard and read other say it, that factory remanufactured transmission, let's say, by GM or Ford, transmissions that come with a warranty, such asGM's 3 year, 100k warranty, are the best bet, by far. Honestly, that's more miles under warranty than a new OEM, in a new car (3/36).

Ergo, I disagree with those that steer you away. If the vehicle does everything that you need it to do, and you've had the rest of the vehicle inspected to ensure no other major problems are likely to occur, in the near-to-intermediate term, replacement in, let's say, a Silverado 2500 would be a good investment. What can you get for $3-4K, anyway?

It's like everything else. Gather verifiable data, assess cost/benefit/risk and make an intelligent choice.