What are the limits?

[IndigoMKII]

The NA is a rugged drivetrain, the gearbox lives behind V8's in other vehicles, the diffs aren't troublesome in the slightest.
Enjoy the fine car Toyota built years ago, when they were truly world leaders in engineering and reliability.
If the age of teh car worries you, spend money on maintenence.

What car has the w58 mated to a v8? If the w58 is so rugged, why does it crumple when decent torque is thrown at it?

At the OP, if you're worried about breaking it you probably will. Make sure everything is in great condition before you start beating on it. My .02

 

[MPR]

The delivery of the applied power is what breaks stuff. It's the difference between setting a ton of bricks down gently and dropping a ton of bricks. Which will be more destructive?

You can have a lot of power going through various components safely or you can slam those components with the same amount of power and be abusive. You can save such components if you learn proper techniques and driving styles that isn't so abusive. Slamming gears and dumping the clutch while bouncing off the limiter will not necessarily make you go any faster.

 

[IndigoMKII]

The delivery of the applied power is what breaks stuff. It's the difference between setting a ton of bricks down gently and dropping a ton of bricks. Which will be more destructive?

You can have a lot of power going through various components safely or you can slam those components with the same amount of power and be abusive. You can save such components if you learn proper techniques and driving styles that isn't so abusive. Slamming gears and dumping the clutch while bouncing off the limiter will not necessarily make you go any faster.

Never said you have to abuse a transmission to kill it. I'm merely saying the one time something does hook up good enough things will break. Like doing a burn out and trying to go into 2nd, only takes one time..

 

[Backlash2032]

In my experience, the clutch will go before the transmission. When I first got my car, I could bark second in a straight line. Before I took it off the road, the clutch would slip long before the tires. These are pretty stout cars. I wouldn't really be worried about breaking things unless you are just stupid. 2nd gear burnouts, powershifting, dumping the clutch at a stupid high rpm, all fall into this category.

Shock is what kills transmissions 90% of the time, not load. When was the last time you heard of somebody dropping their trans doing a highway pull?