Stovebolt.com Forums The Parking Lot Big Bolts Strange knocking sound

I won't be doing anything with this till spring, but wanted to get some ideas. It's on the '59 Viking 40 I just got.
I got the 283 running, and it actually runs quite well--sat there and idled as nice as could be. But when I drove it around the yard it sounds just like a rod is knocking. I assumed the worst and that the engine was knocking because it was now under load.
I mentioned this to the PO and he and his brother both said , "it's not the engine--it's the transmission--it's done that for years."
So I'm thinking--"how can I put the engine under load without the transmission turning in order to test this?' So I drove it up against a big oak tree and lugged it down. Even killed it once. No knock! So apparently they were right. It must be in the transmission or drive train somewhere.
I haven't driven it out on the road yet or at high speed, since it currently has no brakes. Just around the yard in first and second gear. It also does it in reverse.
As I mentioned, it's getting too cold to do anything more with it now, as it won't fit into my shop. We'll look into it in the spring. But just wondering if anyone had any idea as to what might be going on in there.
Thanks in advance!
Sorry this got to be so long!

Does this rig have a transmission mounted park brake?

Your U-joints could be bad causing a snapping sound. To check them chock the tires so the truck can't roll, then release the parking brake and put the trans in neutral. Now slide under and twist the drive shaft back and forth and see if there is any slop in the U-joints.

You shouldn't have to wait till spring to make this simple test...

Mike B

It does. I used it when we were towing the truck home, as the other brakes are not yet working.

Mike, I'll try and get under it one of these days and double check those U-joints. I was under there once, and they didn't seem too bad, but probably worth checking again.

Jack up both rear wheels and support the axle tubes with heavy duty jack stands. Start the engine, put the transmission in gear, and listen for the noise. Then carefully inspect all the moving parts to see if you can locate the noise. Stay well away from the moving wheels if you choose to crawl around under the truck.
Jerry

All good recommendations, but I like the KISS principle. A loose transmission brake can make a lot of noise.

Just curious, what's your oil pressure. I would suspect U-joints also. Mine is 160.5" wheelbase with 3 piece drive shaft and two midship bearings - lots of chance for noise in this set-up.