Well, put the '04 2500 on the lift yesterday, and sprayed the snot out of it using Eastwood's Anti-rust
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Did make it look better, if nothing else, and I did the oil pan which was rusting badly (I've friends who have had rust through on their oil pans).Will report success or failure in the late spring next year, if I'm still alive!
If nothing else, it still is running good since I did the U joints. At least that was a cheap repair for parts, only $20 for the joint! A PITA to change, had to press it back and forth three times to get the cups out, they were that tight!