Rod knock? and other bad things

[Old Blue]

To Me it sounds like it is coming from behind the engine, maybe fw or fork or to bearing?

Does engaging or disengaging clutch make any difference? I see the truck is in 4Low how about both trans and tcase in neutral? What happens if you wiggle the clutch release fork when running or hold onto it do you feel a knock does it change? sounds like something outside the engine to me...does not sounds like a bottom end knock..but not familiar with one on this engine...

Check your clutch. Remove the bottom cover then start. If it is rubbing the cover, it will make a similar sound. Check the simple stuff first before pulling the motor.

I showed my grand-dad the videos and he agrees 110% he thinks it's behind the motor on the clutch or transmission as well. He was a mechanic for almost 40 years on school busses and he knows the sounds, like some of you seem to as well. He also made mention that something dragging back there could make a feeling like a tight spot in the engine also. I'm putting it on a trailer and taking it down to his place so he can listen first hand, then I'll take the inspection cover off and go from there - sounds like it might be a simple fix, I'll keep you all posted!

Trans and case in neutral makes no difference, clutch in or out either. I'll try wiggling the fork with it running and see if that makes a difference while I'm at it. Thanks for all the suggestions so far, it's really been a help - my head about exploded after doing all this work and then hearing that rapping noise -- I was NOT happy last night! You guys are the best!

 

[riotwarrior]

Just a thought....and I know this is out there....take a very close look at your harmonic balancer...I have heard a hard metallic knock like that from a bad harmonic balancer previously....changed it and viola no knock It could also have a rub that seems tight too, might not have to load it on the trailer!

 

[Old Blue]

Well I trailered the truck down today, but I found and fixed the 'knock' before I loaded it up. It was the inspection cover hitting the flywheel on the drivers side, up by the oil pan, just as stated above - simple fix! Now the truck will be down at my grandad's place so he can get out of the house and help me out a little bit here and there since he broke his hip - he's going stir crazy and grandma won't let him get into much without a chaperone...

Thanks again for all the good suggestions it really helps!

 

[firehawk]

Glad you found it. Ever better that I got it dead on.

 

[icanfixall]

Terrific find and an easy fix too. This forum is ausume isn't it...