"Rattle" Noise Around the Crankshaft Pulley Area

[bwguardian]

Thank you, bwguardian. I am pretty sure the flexplate IS the problem.

My uncle mentioned that he thought the starter seemed too loud, like the gears were not engaging correctly, even though it started right up. I thought the noise was coming from the crankshaft; my uncle thought it was in the oil pan, and the starter is very loud. He even mentioned the noise sounded like sheet metal vibrating on something. It all makes sense now.

Is my starter now damaged if the flexplate is damaged? If I replace the flexplate, will I need to replace the starter at the same time?

Glad I could help...starter should be fine, mine was in both instances.

[RickFury]

Well...I went through the trouble of dropping my AOD transmission to check the flex plate, and the flex plate isn't the problem.

What else could it be?

[TWR2003]

Well you have eliminated most of the 'easy' sources of that type of noise. Im thinking that you have a main or rod bearing that is gone. How many miles on this truck? What is your oil pressure (on a real gauge not the factory one)?

[RickFury]

Main or rod bearing? Please tell me you are joking. Would a bad bearing make a "rattle" type noise at idle and go away under a load?

The engine has less than 3000 miles on it. It was rebuilt two years ago along with the transmission. What would cause a bearing failure in that short of time?

Oil pressure seems normal. i don't have a true oil pressure gauge, only the one in the instrument cluster. It registers about the same as it always did. Around the "A" on the NORMAL scale at start-up, and settles around the "O" during normal cruising.

[Marz]

I wouldn't put too much faith in the factory gauges.

[MAD MIKE]

Well...I went through the trouble of dropping my AOD transmission to check the flex plate, and the flex plate isn't the problem.

What else could it be?

Did you rap on it with a hammer to see if it rang like a bell?
Small fractures and cracks can cause rattling and ringing of the flexplate.

[82GT_t-top]

Being the starter is loud I have seen a few starters that the bendix was falling back onto the flywheel teeth due to the spring I'm the starter getting weak. They weren't engaging all the way back on the fly wheel but just enough to make a metal rattle sound kinda like a fork hitting a heat sheild.once the engine wasrev up it would kick the bendix back .

[RickFury]

I just had a good friend check it out, who owns his own transmission shop. He did find the starter was binding up some, and he rebuilt it for me. He inspected everything else, including the flex plate and replaced the torque converter.

The rattle is still there!

Using a screwdriver as a stethoscope, he told me that the noise is coming from the front of the engine, but he is stumped too. He doesn't think it is a rod or bearing noise.

[RickFury]

OK, I found a certified mechanic to put it up on a lift for me and he checked everything out with a stethoscope. He narrowed it down to the area around the fuel pump. Even though the old fuel pump looked fine, I replaced the fuel pump, and the noise went away.

When the truck is warmed up, the rattle comes back. If I let the engine cool, the noise is gone until it warms back up, and then the noise returns.

What does that mean?

[RickFury]

*** UPDATE***

The problem has been found. The noise is a rod knock.

[Vinnietbird]

*** UPDATE***

The problem has been found. The noise is a rod knock.

There's a GT40-P engine for cheap in the classifieds..........now is a good time for a swap, and it's a one day job...........