Perplexing sounds after new... everything

[Calan]

First, here's everything that is new and what's been done:

1. Tranny rebuild (local) and replaced transfer case seals
2. ACT 2600, Streetlite flywheel
3. Mitsu TOB, fork, and pivot ball from dealer (washer under ball and extended rod)
4. EvoIII turbo, mani, and ported O2 housing
5. Forced Performance FP1/FP2 cams
6. Revised lifters
7. All new timing components (OEM from dealer)
8. Alternator and starter (Autozone)
9. Axles (both sides - Autozone)
10. Ported oil filter housing
11. New ECU with custom chip from Jeff (Keydiver)
12. All new seals/gaskets including front case, rear main, etc.

What seems ok...

After idling a while during timing/BISS adjustment, looking everything over, warmup, etc...I took it for a drive of about 6-7 miles. It goes in and out of gear fine (although a bit notchier than before), and I believe the clutch is now bled and adjusted fairly well. The master and slave cyls look fine with no noticable leaks. The car accelerates and seems to run well, other than it hasn't been tuned at all yet so there were some occasional counts of knock when accelerating. Small vibration under braking (expected due to 3 months of the rotors/pads in open air; got better as I drove). And of course the normal burning off of paint and oil and getting used to the car again

What is definitely not ok....

I have a "rattle" type sound coming from the bell housing area. It's very noticable when I'm in neutral and the clutch is out, or when I'm decelerating (it doesn't change in pitch with speed). It's almost like something just randomly rattling around lose. I also heard a sort of whining/whirring noise for a brief moment while cruising in 4th, but couldn't isolate it. Oddly enough, it seemed to disappear when I turned the air off, although it sounded like gear whine and not a belt. It didn't come back after that as far as I could tell.

As discussed in this thread, I now know I put the clip on the TOB incorrectly (upside down), but it doesn't seem likely to me (and others) that it would cause this.

My first thoughts are either TOB or input shaft bearings in the tranny. But all of this is new, and the guy that did the rebuild assured me that the bearings and everything else are new as well (and he has done many dsm trannys and is reputable around here from everything I've heard).

Any other ideas or thoughts on this? Could that momentary whirring I heard be a part of it, or is that something else just trying to find it's "home"?

Any thoughts and ideas greatly appreciated... especially if they don't involved pulling the damn tranny again

 

[Calan]

Some updated info:

Just took the car out for some driving...here is some more info on the issue(s) I'm having.

The loose rattle sound is there during idle in neutral, but goes away when the clutch pedal is pressed.

While driving, I have a similar sound only it's more like chattering than a loose rattle type sound. It happens in any gear while cruising at steady speed or decelerating (decelerating is much louder), and is more noticable the higher the RPM. Above about 3K RPM it gets rather annoying, and when you pull your foot off the gas at that RPM it gets down right scary sounding ... and I never took it much higher than that.

It seems to go away while under any acceleration, and pressing in the clutch (any gear), coasting in neutral, or turning the car off and coasting causes the sound to go away completely...or at least below the road noise so it can't be heard.

EDIT:

I had another thought (more like wishful thinking ... the flex section of my downpipe is up against the bottom of my oil pan at the moment. Could the torque of the motor/tranny during steady speed and deceleration be causing it to vibrate against the pan, but not when the other conditions are met that cause it to go away?

 

[96gstdsm]

That sounds to me seems like it is your TOB (throw out bearing) That is exactly how mine sounded when it was loose. Mine would always go away when you the clutch was pressed in. It sounded like a few marbles were loose in my tranny and bouncing around. If that is the case it is not really harmful or anything to drive with it like that, but just very annoying. If the TOB that was used was a metal sleeved one than this is pretty common. I know ACT used to supply metal sleeved TOB's and not the oem plastic ones. I believe they updated that(did for mine about a year ago).
I would highly doubt it being the flex section of your downpipe. Try slipping something soft in between the flex section and the oil pan and see if changes it sound.

 

[Calan]

Ryan... did you have the same chattering sound at steady speed and decelerating that I mentioned, or only at idle?

Thanks

 

[96gstdsm]

I had it always except when my clutch was pressed in. Seems to get louder if I remember correctly though when the rpm's went up. But definitely sounded like marbles bouncing around everywhere. Was a pretty bad sounding noise.

 

[Calan]

Well I was able to isolate the sound to the rear (passenger side) of the tranny. When I drained the Pennz SM, it looked like there is a little very fine (almost powder) brass in it. So I dropped the tranny .. and there is probably 1/8" of play in the output shaft, and a little up/down as well. When I yank it around by hand, I get pretty much the same sounds that I was hearing during idle, back around the center diff/VC area.

Anyway, the guy that rebuilt the tranny is going to tear into it and see what happened.

How much play should there be in the input and output shafts? I would think it is down in the .005" range at least.

Should I pull my new pressure plate back off and see how the clutch looks (after 25 miles or so on it , or just leave it? Everything looks fine from the outside, and the alignment tool fits like a glove. And there was never a problem shifting or with clutch engagement.