I need help diagnosing a knock in my engine. The previous owner said he put it in the shop to have the transmission rebuilt and after it came out something popped and it started knocking.

I'm pretty sure it isn't in the transmission but i have no idea what it is or if it can be fixed or if the motor is done.

Here is my best attempt at describing what it's doing. The truck has 126k on it and it starts fine and usually the knocking starts right away but sometimes goes away at idle. I can move it around but any good blip of the throttle makes it die. If you ease in to the throttle it will stay running. The exhaust was cut for some reason so that is the noise you hear ticking in the videos. Oil pressure is fine. The oil looks clean as far as the dipstick goes.

This was a cold start so it stays rev'd for a bit in the first video. I gave it some throttle a few times to hear the knock and see if it would die. It didn't die on it's own in the first video with a few revs but it did die on it's own in the second video. The knock is not consistent. It seems to come and go. Sometimes you can rev it with no knock and other times like in the video it will get louder with revs.

So what do you think, is she done? I appreciate the help. Thanks in advance.

 

Sounds kind of like something external to the engine.
Try taking off the belt and starting it for a moment to see if it still does the noise.
While the belt is off wiggle all the pulleys.

 

I didn't think of that. Thanks, going to try it tomorrow.

 

I agree with SamIAm, that doesn't sound like anything internal. Other thoughts, check the exhaust and heat shields. Also, what transmission work? If the transmission came out, pull the front cover and make sure the torque converter got bolted up tight to the flywheel. Check the flywheel for cracks. A cracked flywheel can make some crazy sounds.

 

My first thought was also the torque converter bolts.

 

Im going to say piston

what do the cylinder pressures look like

 

The transmission was rebuilt. According to the PO they had hell getting the transmission back in. Our initial that was a cracked flywheel but we checked the flywheel by bumping it over and everything appeared fine.

 

The reason I don't think it's a torque converter is it would not make that noise at idle...would do it when the torque converter is locked

 

What ended up being the problem?