So completed my swap and love the new tranny! It's a built 4L60 with yank 4000. Computer doing the shifting. Is there certain donts? Am I ok letting it shift into 4th at Wot? Or flooring it anytime going down the road? Just don't want to hurt it after all that work lol.

 

Its unlikely you will shift into 4th at WOT unless you are at Bonneville.

Most important is to keep it cool, especially with a 4000 stall. What kind and size of cooler do you have?

 

Don't have the part number on me right now but it's roughly a 10x14" B&M mounted in front of the condenser

 

Good; wanted to be sure you had a decent cooler.

A general guideline is to reduce WOT downshifts and instead, when possible, downshift manually and then go WOT. While many people here have their torque management disabled, keeping at least some torque management enabled will extend the life.

 

Gotcha, so if I'm cruising at say 45 in 3rd, I can downshift to 2nd and it won't hurt it?

 

Yes, moderate/low throttle manual downshifts are fine.
I'm not sure of this - never tried it - but I think the PCM will protect you from accidental downshifts that would overrev the engine.
Anyone know this for sure?