Annoying rattling sound still there!

[Lorne G.]

My annoying rattling sound is still there. The sound is coming from the bellhousing area and I was convinced it was a weak starter drive return spring or inspection shield rubbing against flywheel or starter. I replaced the starter with another one, left the inspection shield off, took the car for a drive and the annoying sound is still there.

Now I am thinking it may be a ring gear problem. Would a loose or worn ring gear make a rattling sound under load only from 2200 rpm and up? The noise stops when I let up on the gas peddle and starts as soon as I accelerate again.

I just installed a TKO600 transmission and also wonder if I have an alignment problem with the bell housing. I am not looking forward to the idea of trying to remove that transmission since it will not come out from underneath in a big block.

Any ideas where or what to look at?

Lorne

[Paul O.]

Re: Annoying rattling sound still there!

Lorne have you checked the heat riser that could be your problem. Use some steel wire and lock it open and see if the noise goes away. Paul 18046

[Lorne G.]

Re: Annoying rattling sound still there!

Hi Paul, yes I tried that already. I went as far as to remove all splash shields, rocker moldings and even side pipe covers to see if any of those were rattling. The sound seems to be coming from the bell housing area.

Lorne

[James G.]

Re: Annoying rattling sound still there!

Check for a broken motor mount. When you accelerate it is strong, decelerate it goes away. The engine may be rotating right and left. Double check the fan shroud for fan damage. Sometimes these type of noise sound different.

If possible, put the car on a lift. Get a friend to be under the car. You ride up and start the car. Now you have 4 ears, and a different set of eyes, and location looking for the problem.

[Lorne G.]

Re: Annoying rattling sound still there!

Thanks James, The motor mounts are new. I jacked the rear wheels off the ground and went through the gears up to around 3000 rpm with no noise. The noise only happens under load and i guess with the wheels off the ground there is not sufficient load on the driveline.

Everthing under the hood has been checked and re-checked making me think it is coming from the bell housing area.

Lorne

[Tom H.]

Re: Annoying rattling sound still there!

Drive shaft isn't rubbing anywhere is it ??

[Jack H.]

Re: Annoying rattling sound still there!

By any chance did you happen to pull the inspection cover to see if there's any stray debris/parts floating around inside the bellhousing?

[Albert P.]

Re: Annoying rattling sound still there!

Don't know if you have ignition shields installed but may be loose.

[Stuart F.]

Re: Annoying rattling sound still there!

I don't recall from your first report about this noise, but let me throw out a few more prospects from an old man's experience; I would ask if the engine is performing to at least it's pre-noise level. If not, does the timing look right with a timing light, i.e. no sign of it being erratic, etc.

The one noise I have come across that was equally hard to diagnose was a broken crankshaft - on three Chevy V8's. It sounded like something broken and rattling around in the bell housing and we expected something amiss in the clutch. It would only do it under load, not on deceleratio.

Beyond that, you have to revisit any changes or modifications you have done just before this problem. That is the old Chevy Man "Rule of Thumb". What did you change???

Stu Fox

[Lorne G.]

Re: Annoying rattling sound still there!

Jack, yes i did pull the inspection cover as i thought it may rubbing. I did not see any debris but I have not really driven it very much either since the noise started.
Stuart, I have started to work backwards and look at everthing that was done or replaced.
The car ran flawlessly before I decided to pull the body, do some frame and engine detailing and install the TKO600 5 speed transmission.

Since the engine ran perfectly before, I ruled out the engine for the cause of the noise. I removed a lot of parts like moldings thinking that they may be the cause of the rattling. Eveything that could rattle under the hood and under the car has been checked which now leaves the bellhousing and transmission area since major changes were made here.
I was hoping the problem would be elsewhere because I really hate the thought of pulling the tranny. I installed it with the body off so it was easy then.
I am tempted to drive it for a while and if something is rubbing or wearing in the bellhousing area, then evidence should start appearing like metal dust particles..........or is this a bad idea?
I am going to buy a stethoscope at NAPA to see if I can get a more accurate noise location.
If I jack the car up, run it through the gears, and apply the brake slowly at the same time, I may be able to create sufficient load to cause the noise while having a couple buddies up front with eyes and ears.

Lorne
Lorne