OK, Bought a 07 with a couple problems today.

[SpareParts]

After changing oil i let the pan sit for close to a week (mostly because i was lazy but curious)
After carefully draining the pan this was in the bottom. Lots of sparkly stuff!
Nothing is going to fix that.

 

[petethepug]

Our 08 Denali had scary piston slap below 50* at cold start up. The 40k and six years we had it, nothing came of it. The new owner I sold it to knew of it and appreciated the heads up.

I’d slip a new TC in filled w/ fresh fluid and service the trans, fluid & filter. Press the trip reset button and wait for another 100k.

 

[SpareParts]

Our 08 Denali had scary piston slap below 50* at cold start up. The 40k and six years we had it, nothing came of it. The new owner I sold it to knew of it and appreciated the heads up.

I’d slip a new TC in filled w/ fresh fluid and service the trans, fluid & filter. Press the trip reset button and wait for another 100k.

After seeing what is in the bottom of the pan after a normal oil change this advice makes no since to me. If you are saying just run it.
Servicing the trans however does with out a doubt.