Gary and others,

Buying a Prevost is not a case where you kick the tires and see if you like the colors. It is a complex event that only begins when you and the seller strike a deal on the price. I think somewhere is a guide (POG home page maybe?) that can be printed out by prospective buyers and in it I talk about having DD and Allison run the codes. You do not have to check a drain plug because it doesn't necessarily tell the whole story. But having the experts connect to a computer and review the current condition and pervious codes will help substantially.

I don't know if your transmission ills would have been detected, but I do know the Allison diagnostics are superb and can tell you a lot about the current condition. They will give you a graphic report showing considerable detail including clutch wear and life remaining. Whether it would show if some hack did poor quality work I can not say.

Pulling a drain plug on the engine or transmission is an expensive thing. Most transmissions have Transynd which is now carrying a price per gallon just slightly below the CA debt level and I am not sure the drain plug on the tranny has a magnet. What I would suggest, which is what we do with planes is to remove a filter, cut it open and examine its contents. You will have far less fluid loss and you will see a much more detailed accumulation of the crud that may be floating around in the fluids. Not all debris is going to be magnetic, such as clutch material and copper or aluminum particles.