Rattle noise at 2200-2300 RPM in Drive

Hatdragracer

Member
Joined
Jul 2, 2012
All...I have searched relentlessly for threads discussion rattles, and have tracked down the possible sources I could locate and possible sources discussed here. The car has always made this noise, but since the rebuild the rattle has gotten louder.

I have recently rebuilt the engine and done some upgrades (in sig) and the car is running fine. I have searched through many posts on rattling and still have not been able to locate.
Since 2013:
Rebuilt Engine
New Alternator
New PS Pump
New Tensioner Pulley
Verified Tensioner has correct belt (60635) and is operating in the “window”
New Exhaust system from downpipe to tailpipes (No Cats or heat shields)
New HR Poly Mounts
New Tranny Mount
New Torque Converter (PTC 3000RPM lockup stall, flexplate and torque converter bolts are tight)
Have had to two different tranny shops, they are both telling me the noise is not from trans
No PCV Valve
Verified Damper bolt is tight
Verified Crank sensor has clearance and not hitting damper ring

Rattle is consistent at those RPMS (2200-2300)
Rattle is louder when cold, quiets down somewhat when warm
Rattle is loud and can be heard from either side of the car, It is not an interior rattle
Rattle only happens when in Drive, does not make noise when in Neutral or Park
Rattle is only heard during low throttle application, under normal or hard throttle the noise is not heard
Rattle is heard in overdrive cruising at highway speeds where the RPMs are 2200-2300
Rattle is there with and without the converter dust shield

I have spent the past few weeks focusing on finding this rattle and am at my wits end. Last night I removed the alt, and tensioner, ensured all the accessory drive bolts were tight and I drove car (briefly) without accessory drive belt, noise was still there.

The car still has its factory manifolds, those heat shields feel solid to me.

Any ideas on where or how I could continue the search would be greatly appreciated
 
I had a similar problem but it wasn't at a specific RPM. It turned out to be part of the shift linkage; the rod that runs up from the trans
(along the firewall) to the steering column was the culprit.
 
I put some of that foam insulation (split tube type) around the rod and put some extra washers on the linkage ends to firm it up a bit...
You might also try to jack up the rear of the car and run it to see if you can locate the gremlin.
 
What valve covers are you running? Some aftermarket valve covers just touch the heater box heat shield under light throttle.
 
When I got mine the rubber grommet in the center of the hood at the base of the windshield would make some crazy sounds( squeak, vibration) and one day when looking for the noise I had oil on my hand when I touched it and no more noise!
Also spent untold hours looking on the Syclone and finally had the driveshaft end cut off to find a 2' piece of metal inside of it!
Good luck, Jon
 
I have had the same issue I actually got it on video unfortunately I can post from this app . I changed the fluid and filter in my trans and it went away
 
On my cat my metal inter cooler shroud was rattling, and also the big bracket that holds the AC compressor, PS pump, and alternator was loose. Took forever to find it.

Posted from the TurboBuick.Com mobile app
 
I have the cast GN1 performance valve covers with the 45degree breathers, they look to have a little clearance...but I'll start with that idea and the shifter....trans service is most likely due soon anyway....thanks for the ideas

Posted from the TurboBuick.Com mobile app
 
The hood center Grommet is an interesting thought...wouldn't have thought of that...It does look like it has been making solid contact with the hood and looks pretty worn...I hope its something that simple!

Posted from the TurboBuick.Com mobile app
 
The hood center Grommet is an interesting thought...wouldn't have thought of that...It does look like it has been making solid contact with the hood and looks pretty worn...I hope its something that simple!

Posted from the TurboBuick.Com mobile app

I had this when I bought my GN, thought something was loose in the dash when ever it hit a bump in the road. A little dab of grease and it was gone for good.

My valve cover only has about 1/8 clearance and touches when I make right hand turns mostly. I can just see the clearance under the car on the passenger side, or if I lift the wire loom out of the way from the top side.
 
2 second test.... Drop of oil on the hood support. Report back.

currently cutting it the F loose
 
My ignition control module let go on Friday....so I am in a holding pattern until I upgrade ignition. I will update with what results I find.

Posted from the TurboBuick.Com mobile app
 
Go out and push across the hood a couple inches back from the windshield. Its the back and forth motion that does more so than not.

currently cutting it the F loose
 
Update:
Tried a drop of oil on each of the hood supports - Rattle remains
Changed the shifter to a spare shifter I have, tried readjusting - Rattle Remains
Checked fastners on front sheet metal/inner fenders ...including fan shroud - Rattle Remains

Will service the trans this week and see what happens/

Any other ideas?

Is it worth me posing video/audio of the rattle?
 
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