tranny?

[tphsmith]

transmission? u-joints ?

I drive an 81 1/2 ton with straight 6 in it. I assume the transmission maybe is a 350. well when I put it in gear it makes a loud clunk noise. I thought ok look at the u-joints. I dropped the drive shaft. and I have not yet removed the u-joints from the drive shaft yet but the seals look good they are not dried out. the joints I grab in my hand while the joints are still on drive shaft and I have drive shaft on the work bench. I dont see any unusual movement from the u-joints. so I started the truck with out drive shaft in and shifted from reverse to drive no noise sounds good. but when I put it in park with the motor running it makes a noise that I dont like................ HELP