Engine/Trans Seriously Bad Noise

Do you have a harbor freight near you? I just got one of their flyers and they have an inspection camera on sale for only $70. It's probably a cheap one but if you don't need to use one much it would probably do the job. If the trans turns out ok, which I bet it does, the camera may come in handy to look into the cylinders to see if a foreign object is in it. About 30 yrs. ago when I was a kid I had a baseplate screw drop out of a carb (open plenum intake) and it went down into the cylinder and sat on top of the piston and made the same type of noise you say yours is making.