Was there metal in the transmission pan? There should be if the torque converter is failing. Also the torque converter vibration would be based on engine RPM not car speed. Vibration caused at a certain speed in the back would be between the output shaft on the trans to the wheels.

 

The fluid was beautifully speck free. Even the postage stamp-sized pan magnet was metal free. I wish you could see the vids I took. It would make at least a better anecdotal assessment more valid . The diff was also in virtually mint condition-fluid & gears.

You were right about the vibrations/sounds transferring from a-z in the driveline. After being underneath, right next to the transmission and examining the videos, I'm about 99% convinced it's torque conv shudder. The trans has always shifted perfectly through each gear before and after fluid change, btw.

Lubeguard shudder fix seems like a "quick fix" prayer, like so many 'quick fix' crap products off the shelf that usually result in just a wasted prayer. However, it won't hurt as a last resort I suppose. And, yanking a tranny out while on my back isn't fun. The Lubeguard looks like it adds conditioners for the torque conv clutch that the old fluid loses. The new new fluid is supposed to recondition the fluid I thought. It's a pretty tiny tube so it's going to be a pretty diluted concentration anyway. I don't see it causing any peripheral issues.

Maybe the wally world Dex lll I used had lower quality conditioners.

 

If you have a google acct I have them saved up to Drive to share. I'd love even an anecdotal assessment or more advice.

 

Here's a list of replaced stuff so far after 13 year hiatus:

refurbished fuel tank myself (cheap) with: 14 gal vinegar (soaked for 3-4 days), baking soda to neutralize, electrolysis for 3 days-on and off, pressure washer, heat gun.
fuel lines cleaned: metal with evaporust & plastic with just water.
fuel rail cleaned
cleaned all internal cooling system components with commercial flush and evaporust.
cleaned all external brake components
new fuel pump ($72)
new fuel injectors ($80)
new fuel injector retaining clips ($3)
new fuel regulator ($28)
new fuel filters (2) ($14) After circulating fuel through system a few days I put a second fresh filter in just in case.
new fuel line connector & union ($42)
new fuel vapor canister purge valve ($25)
new Idle Air Control Valve ($10)
oil change/filter penz plat full synth high mileage ($33)
cooling system comprehensive flush ($30)
new window lift motors ($35) + (adv auto warranty)
used aluminum driveshaft with yoke($140)
new Spicer u joints ($65)
new oem transmission Mount ($14)
changed transmission fluid & filter kit ($24)
changed diff fluid & lube locker gasket ($40)
new coolant temp sensor ($25)
new Dorman A/C Compressor Bypass Pulley ($43)
new PCV Valve ($3)
new front stabilizer bar bushing-pass side ($11)
new tires-front ($200)
===============================================

 

Wow, could have put $8 shudder fix in it 5 months ago and saved a bunch of $. Although, a one-piece aluminum shaft is nice to have. And, getting a peek in the diff & trans was nice, especially after sitting so long. The power isn't like I remember, even though it's a dinky 3.4L. I'm going to hook it up to Gary's Scan9495 manana to assess some data. I wonder if the Chinese injectors were TOO crappy. The scan may be able to tell, hopefully. The exhaust pipe about halfway between muffler and Cat was SPRAYING two streams of water out pinholes in the pipe so god knows how much condensed aqua has settled in there. I wonder also if there's remnant's of a mice encampment in there. I've found several snake skins under the hood over the years and I've seen a decent size black snake in between the hood insulation and the hood skin several years back.

 

keep an eye on the coolant level. wait for engine to cool completely and check level in radiator.

 

I should have clarified that the spray was back when I first got it idling several weeks ago. It hasn't done it since then. I thought the same thing you did though and thought it may have come from a blown head gasket but it was clear and odorless.

The bit of shudder left manifest's itself at closer to 60 mph now but it's much less severe.