How does shifting down in to 2nd hurt the tranny? If you are going at a speed that is at the bottom of 2nd gear, and you shift when you are not on the gas, then the logic in my brain says it won't hurt... ???

it will hurt because you can wind 2nd gear out to the rev limiter when the shifter is in 2nd, when the gear selector is in 3rd, it will shift at the normal WOT shift point.

The big point of this is that there is no reason to put the transmission in 2nd to "exercise" the engine, i can do nothing but harm

That is what the Caddy apb says...

Very well, I'm open to hearing how this method works, but so far no one has told me HOW this works, and why its beneficial.

I wouldnt want to do this to a warmed up 4T80E with over 100K on the ticker, blow something, go to the dealer and my only argument is...there'* a Caddy APB on it"

D'jknow what I mean?!

Isn't the northstar variants of engine designed to use a little bit of oil to keep the cylinders well lubricated? I don't have an issue with excessive use of oil between oil changes. Just the typical half quart or so every 5,000 miles.

I'm going to guess 2nd gear will allow higher RPMs at lower speed(going 85mph is safer than 120mph, IMO) or I am just dumb.

He told me why... But I have since forgot... Opps

I don't see how revving the engine to redline will "hurt the Transmission." I agree that the lower gear will keep the MPH down. I dont see why this couldn't be preformed in 1st gear, other than the motor will hit the redline sooner.

the trans will be spinning faster than it is 'normally' desinged to, thus creating excessive heat.....if this is done repeatedly the heat will kill the trans

WOT to clear carbon? Carbon is a by-product of a rich condition. At WOT, most engines run full rich. WOT INTENSIFIES the carbon buildup problem.