2003 Oldsmobile Silhouette Transmission Problems

Hi well there should be a slight selay when going from neutral to drive. The first delay you were refering to sounds like it was just low on fluid due to the leaks you had repaired.

However when you can sometimes go from park to drive and trans works normal. This sounds like possibly a computer or sensor prob.
However if this was the case the trans shop would have found this with a scan.

METALIC PARTICLES. Yes more then he would like to see. This means although you don't have a trans prob at the moment your transmission is certainly wearing out a metal part internally.

My advice drive it if the trans is going to go it will no matter what. But this could be thousands of miles away. Had they seen an immediate prob they would have told you. So I wouldn't worry too much

Yes that is a possibility. But still the trans shop would have adjusted trying to diagnose. If the selector lines up when in gear then it is properly adjusted. Prob in reality what you have is a weak or sluggish pump in the trans. Worn valvebody ports or even worn bands or servo rods could be worn.

This is why most shops will want to do a complete rebuild because there is so many parts then can be worn they can't really pin it down without a complete teardown and lots of measurements.

I know that it seems like a very small problem, but many parts inside the trans will cause a delay first then slippage or complete loss of pressure.