Mystery Noise Under Rear Of Engine (VIDEO)

[swshawaii]

This one's baffled me. Probably coincidence, but started right after replacing my passenger side valve cover gasket. All timing chain components ruled out. Rattle only occurs at idle speed in park or in gear. Probed EVERYTHING on engine top side with a stethoscope with no similar noise. Had the truck on a lift at the best exhaust shop in Hawaii and they ruled out heat shields or any other exhaust components. Thoroughly checked for any loose parts from below. Probed the bell housing and all other parts from below with no similar noises. Transmission is full and clean with Mercon V. I've read of possible torque converter or flex plate issues, but have not experienced any of those symptoms or sounds I've seen on line. Any help or opinions greatly appreciated.

 

[Todd Z]

well well well, that sounds like a piece of plastic is stuck and dragging on the rear chain..... probably either fell in there when the cover was done or a coincidence after the repair...... Or something dragging on the flywheel, but that's a sealed area....

 

[EddieS'04]

Steve, I had loose tq converter bolts on a dodge that did that. It got louder under acceleration the n stoped under cruise.. I tighten the tq convertor bolts on the flex plate and it stoped.
Just throwing that out there.... Did you use the stethascope on the bottom side while in the air.?

The shop ruled out a exhaust converter loosening internal.?

 

[swshawaii]

Manager at Exhaust Systems Hawaii is 99.9% certain the noise is not exhaust related. I've touched EVERY reachable part under the Trac with the stethoscope without finding a similar noise. First things that came to mind were the torque converter or flex plate, but the only way to thoroughly inspect both would be dropping the tranny. Funny thing is I removed the tranny dipstick several times to check the fluid level after driving with the engine warm and the noise STOPPED. I'm having a difficult time getting an accurate reading when the fluid is clean and almost transparent, even in bright sunlight. Dipstick tube and dipstick are undamaged and fastened correctly. I'll report back with my findings. Thanks for the feedback.

 

[EddieS'04]

I didnt' pull the trans. I took the bolts out of the lower plate. Then bent it back so I could see the bolts.
I had to use a 17mm open end and a hammer to tighten them. No room for a box end. That was on a 2.5L dodge though.

 

[John Zuber]

Cam chain and/or tensioner? I'm not understanding how you ruled that out, but that is what it sounds like to me.

 

[swshawaii]

Sorry, forgot to post a pic with the passenger side valve cover removed. New OE hydraulic tensioner was primed and installed before the video. Visible top part of the of the plastic rear guide has minimal movement and appears in good condition. Noise was coming from the rear underside of the engine. Drained one quart of recently changed Pennzoil Platinum 5W-30 oil, and added 32 ounces of non concentrated Rislone Engine Treatment. Not holding my breath it will help.