G5ALIVE

Little Recap:
After a 15 minute drive, accelerate gradually to 60km/h.
Entering 4th gear with a low rpm (low throttle postion) the car will create a loud deep rumble.
Accelerate to 60km/h, coast for 30 seconds, apply slight throttle, the problem should occur.
Release the throttle and the noise goes fades away.

There is no CEL no DTC no freeze frame DTCs.
All relative PCM data looks good

It does not occur at WOT or even more than 30% throttle.
This issue usually occurs when entering 4th gear but has happened in 2 and 3rd.

Now When I first heard the noise, there were a couple different noises and a few different problems.
But I started to notice the noise shortly after changing my resonator and followed by a Solid engine mount.
So of course the first thing I test is, putting back in the factory motor mount, no difference.
Its not how the exhaust sounds. When this is happening Im at 10% throttle position and has the loudness of me driving WOT beside a wall that echoes,

So I do a tune up: spark plugs, fuel injectors, fuel filter, exhaust manifold gasket and trans cooler lines, check fluid level.
Then I replaced a noisy right axle and a seeping factory seal.
I then zip tied my rear O2 sensor wire extension out of my intermediate steering shaft's way.

A week goes by and I notice my right axle seal is spraying fluid and the Trans pan is leaking all the way around.
Techs confirmed axle seal and trans pan gasket were leaking, both were replaced, fluid filled, level checked.

Next I installed a new throttle body and cleaned my intake manifold which had 2-3 tablespoons of engine oil inside.
I did another tune up, cleaning the MAF sensor, MAP sensor, I replaced my pre cat O2 sensor, Intake/ Exhaust VVT solenoids, Ignition Coils, engine oil and air filter.
Inspected exhaust for leaks and intake for vacuum leaks.

Today I am confirming I'm leaking transmission fluid again from the same axle seal.
And the Axle sleeve seems further out then it should be. Shifts are getting more bumpy which lead me to check
What's weird is very lately the Trans temp has been flickering to a much higher number in ~288F which has made me wonder. real momentary data or bad sensor or etc

Spent nights looking at PCM data logs trying to see whats happening.
Slip Speed Requested and Delivered are very close values. Slip speed is zero when occurring (which makes sense after a gear change, right?)

My final suspects are Transmission mounts, TCC component, Torque converter or poor exhaust scavenging.
Tried recording the noise but barely could make it out.

Throwing a supercharger on it in about a month so we can rule out poor exhaust scavenging soon from 1.75" exhaust primaries.
Will be flashing my base tune tomorrow see what happens
Got Solid transmission mounts on stand by

I read an article about someone who was experiencing a similar scenario and it indeed happened to be his Throttle body.
he claimed no difference before and after cleaning and what he found was the calibration was messed up cleaning the blades.
Opening the T-body up with a light acceleration,the T-Body was falling into idle position.
Which kinda feels like an accurate description of what my problem FEELS like.
I noticed no difference using the new throttle body on my car, dont recall messing with the blades prior....

Also want to re torque the intake manifold back on in correct sequence this time. I did test for vacuum leaks, but Im double checking everything.
I snipped the wires to my traction control toggle switch I installed for the winter, knew that would do nothing but I had to try, I can put them back together when the time comes.

I applaud you if you read all my problems-cheers
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The car's last extended warranty expires soon for the dial sticking on PRNDL thinking before it ends ill stop by and let Gm have a chance at figuring it out.
Though Im sure the end result will be "performance exhaust" and an ass raping in diag that will likely be preformed with a bias on the loud exhaust

G5ALIVE

G5ALIVE

should this be sticking out so far from the trans, To me that looks like the intermediate shaft sleeve, which to my knowledge should be about an inch back...

anyway this is whats covered in trans fluid now all the way around the shiny surface here.
1st pic left side of the picture is base of axle shaft, right side is going into the trans
2nd pic top is axle shaft side, bottom is engine side.
Right side 4t45e

G5ALIVE

might have that orientation wrong seeing a little green seal now will look at some more tmr, every day Im reading trying to find more things to check.
Aside from making sure no fluid is leaking ready to wait for CEL and ignore it, hopefully some boost will put be right out of the range of this problem happening ROFL