"Overfilling engine oil can raise the level of oil in the pan to the point where the crankshaft starts to make significant contact with the reservoir. Since it moves so fast, it can turn the oil from a liquid into a froth that the pump is no longer able to siphon and distribute. At that point...
Actually no - we'll do the research, buy the proper equipment, and change the fluid to spec. The new Colorado (my last truck) uses the same procedure as the Toyota more or less. It was fairly easy once you do it the first time.
Regarding trannies in general, if I regularly tow, I change it...
Again, I either have them email the full contract prior to going in or a firm, signed, quote detailing all costs prior to going in including my trade in. That's why it typically takes me 3 - 5 days to complete a transaction.
I haven't negotiated in a dealership in over 25 years (dating myself). That includes trade-ins as well. Everything was negotiated before I walked in the door. I just walk in and sign.
Cash - easy peasy; find the truck you want with the options you want. Manufacturer websites will allow you...