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Cat Man
Cat Man, Cat Engine Expert
Category: Medium and Heavy Trucks
Satisfied Customers: 8413
Experience:  I am ASE Master Truck Certified.
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My names JJ. I have a 3406b that has a knocking noise from

Customer Question

My names JJ. I have a 3406b that has a knocking noise from front or bottom. I got the truck in pieces. Customer had the head removed before I got it. Reassembled with exchange head and had a knocking noise. Put 6 cyl packs new oil pump all new bearings. Taken front apart replace bearing on main gear. Replaced gear and shaft. Still has knocking noise.
JA: Thanks. Can you give me any more details about your issue?
Customer: That's a lot of details
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Submitted: 8 months ago.
Category: Medium and Heavy Trucks
Expert:  Cat Man replied 8 months ago.
Thanks for asking your question. I will try and help you out.
Have you tried breaking injection pump fuel lines loose and see if the knock stops?
Does the engine smoke out the exhaust?
Customer: replied 8 months ago.
sir. No change
Customer: replied 8 months ago.
It does smoke a little
Expert:  Cat Man replied 8 months ago.
Thanks for the information.
If there was no change. I would rule out an injector or plunger problem. Since the head and cylinder have been changed. I must next suspect a timing issue. It could be pin timing or a timing advance problem.
Customer: replied 8 months ago.
It also got 6 nozzles
Expert:  Cat Man replied 8 months ago.
Thanks for the information. I would suspect a timing problem. It could be pin timing or a slipping or miss adjusted timing advance.
Customer: replied 8 months ago.
I'll check the advance in the morning. Customer stated that cyl 3-4-5 were full of water when head was removed. Said the engine was running fine but loosing water. Engine wouldn't turn over was reason for pulling the head
Expert:  Cat Man replied 8 months ago.
Thanks for the information. Let me know if you find anything tomorrow with the timing.
Customer: replied 8 months ago.
No sir everything was pinned and in time. Pulled the advance off checked it out and all is good.
Expert:  Cat Man replied 8 months ago.
Thanks for the information.
If the timing is correct. The only thing left to knock is the air compressor. To verify, you can remove and cap off coolant and oil supply line.
Expert:  Cat Man replied 8 months ago.
Hey. I just wanted to see how things were going. Please let me know if you need more help. I am happy to assist. If my information was helpful, please leave a good or higher rating so that I receive credit. Thanks.
Expert:  Cat Man replied 8 months ago.
Hey. I just wanted to see how things were going. Please let me know if you need more help. I am happy to assist. If my information was helpful, please leave a good or higher rating so that I receive credit. Thanks.