You jogged my memory a tad- the exh tick tick does in fact sound louder under load vs just revving in neutral. His does sound a little different and from the sounds of it, he has checked both exhaust manifolds and didn't hear anything.

I have a V8, not sure if this tick tick is prevalent on the V6 motors.

Had a buddy who’s helped me in the past (lives far away now) take a few min, and he is 95% sure it’s somewhere at the back bottom—torque converter, flex plate, interface etc. I.e., the big clue we started out with that it’s present only in gear. He feels that the tick that’s audible in neutral is a different sound—he feels he can still hear that separately when in gear.

So @alia176 I ordered the chassis ears. When I get that in I’ll do that and the pressurization @MikeinNH67 . Tear down may be delayed a couple days now (looked forward to starting this weekend since I only have the vehicle to borrow until the 21st), I'll keep you posted.

@bob3dsf —THANK YOU for that assessment on the chain system. HUGE help, and I will have the components on standby instead of in the primary game plan. That would save hundreds that may do absolutely nothing (for the sound or anything else).

I have never been so glad to be wrong. Noises are tough to diagnose over the internet. Looks like you are getting closer to figuring this thing out.

Hopefully the Chassis ears will help pinpoint the location of the sound. I can't wait to hear what it is!!!

I've never heard of chassis ears, interesting tech. Good luck finding the noise.

well, what did the Chassis ears produce? Inquiring minds wanna know

Sorry @alia176 , waiting on the ears to arrive threw off my schedule, then life and work projects. Been sitting on the back seat since they arrived. Hope to try on Sunday. Promise to be in touch.

Still work left to do, here's a preliminary report.

1. Chassis-ears aren't fast! It takes some time to find spots to clamp, get each cable routed, out of the way of the wheels, exhaust and hot spots, held up from dragging.

2. It's not easy to find spots to clamp to! There are fewer points to get a regular clamp than you'd think-- at least for areas that matter. Hoses, pipes, wires etc don't matter, and there's plenty of that!

3. Be sure to have a FULLY charged 9V battery...

4. You need to be well-learned in what the types of environmental sounds and carry-through mean to distinguish what you're hearing. Hollow, tinny, echoey... b'c things can be loud but not necessarily be right where you are listening.


So the 9V battery died within a few minutes of just getting started. But these clamps are STRONG! Even clamping onto some of the veins of the block, unsure how it would hold, I drove 10min to Costco and Lowes to get batteries and gas-- gutters, speed bumps, etc. I was nervous and checked each time I parked.... still hanging on!


Since it got late after having to go get a battery, I didn't get to move to other areas, but what I've initially found:
1. It's not in the transmission or drive axle. Definitely quiet there.
2. Don't think it's up top. Very clear and obvious, but not as loud.
3. The side of the block, bell-housing joint to the block, and rear right at the oil pan were the loudest. Each in different states of acceleration, etc.
4. It might be the same tick present in neutral, only significantly louder in gear. Might.

Distinguishing the sounds is difficult-- environment, valve train noise, and this additional noise.

Not significantly different than the stethoscope, but it's giving me more to play with-- slipping it in and out of gear at my own will, accelerating and coasting at will. The carry over of the sound from the valve train, as well as where it's actually clipped can really make it confusing.

I'll post some photos and explanations after I get back another round of it with less rush this weekend trying more specific spots again, including the valve train and all.
@MikeinNH67 @alia176

Listening to the audio, there's certainly a resemblance to the sounds my V8 made when it had holes in the passenger manifold.

Have you done an oil analysis? If the problem is mechanical in nature, there will definitely be metal getting into the oil and it'll be very obvious on an oil analysis. It would rule out all of the rotating assembly & valve train for problems if the analysis came back within acceptable ranges.

Maybe look at this, I've seen it a couple of times. Check the plugs. If they are not seated enough or milled incorrectly compression can get by and cause that noise. I one instance it was a non crush washer spark plug. The bevel was milled incorrectly where it meets the cyl head. The pressure from the compression stroke was getting by the plug. When the plug was removed the witness marks on the plug were only on half the bevel. So the plug was only sealed 1/2 way on the head.

If one of your plugs blew out and killed the threads maybe the others are the failing too?

This is AWESOME with a high degree of nerdery You explained things quite well and the frustrations came across the page nicely. I can't wait for you to figure out the source of this noise.

Thanks for keeping up with this.

Finally got time to mess around. Short story: Nothing finite.

It's more clear towards the rear of the block and possibly on the driver side. This would line up with the #6 plug history (driver closest to firewall). However, it's not absolutely definitive. Some passenger side stuff is clear. Can't define high or low. At least *I* can't. Maybe you can.

@Keros , going to get oil and coolant analysis tools today. @inscarguy , only reason I don't think it's that is b'c nothing changed a bit after I did a valve cover gasket replacement along with all the plugs and a DEEP cleaning with everything open. Not saying it isn't, just lower on the suspect list now.

For those interested in more nerdery, later on I'll drop the audio files with about 11 different positions and comparisons. It's like 15min worth of audio, so you've really got to have nothing better to do with your time!