If I replace my torque converter on a 94 factory turbo idi w/ e40d w/o rebuilding the transmission, and then end up needing to rebuild the tranny, will I be risking damaging the "new" torque converter by driving the truck long enough to determine if that alone fixes my problems? If that doesn't fix my problem, I would immediately remove the transmission again and wouldn't keep driving it shuddering.

I have a consistent and distinct "shudder/slippage" at consistent speeds and scenarios. I've checked/replaced/cleaned/confirmed all of the electrical components are good and functioning as intended. My symptoms went from random to consisten after I replaced the solonoid pack which had a failed internal seal allowing fluid to get into the plug. After that, the symptoms went from random to very predictable and consistent. As I continued to seek confirmation that this is a mechanical vs. electrical issue, I adjusted my TPS from 0.9 V up to 1.2V @ idle. This changed my shift points a bit, making each up-shift a bit later/higher rpm and speed (which I like!) but the shudder symptom simply moved from 30-35 MPH under light acceleration to 40-45 MPH under light acceleration. The shudder/rumble strip feeling is exactly the same still, just at a different speed, I assume due to the TPS calibration change I made, modifying the point at which the electronics signal the solonoid to lock the converter clutch.

@FORDF250HDXLT has been SUPER helpful. Thank you! I'm about to buy a triple disc converter from ebay (unless ya'll tell me that's dumb) but am trying to decide if I'm risking anything other than my labor and bloody knuckles and time to ONLY replace the converter and easy seals w/o doing anything else. The transmission shifts well. No slippage noticed anywhere other than between 30-35 or 4-45 after TPS was adjusted again. Here is a pic of my fluid and pan/magnet when I dropped it to replace the solonoid. No debris but it was brown and the magnet had a fair amount of "hair" on it. Thanks in advance!

 

@MarkKovalsky
Mark will have all your answers, he was a ford trans engineer.

 

If it is only shuddering when the converter is locked, chances are the converter is the entire problem. It's probably worth replacing just the converter.

 

I would also suggest the same at this point in the diagnoses. Like I mentioned in your other thread;
To answer your question directly though, unfortunately, yes. If the trans fails and fills the converter full of metal, it could require replacement again, have it cut apart, cleaned and or repaired. It sounds to me like now that the trans is shifting properly and you're only left with a shutter, I agree with Mark, I would try just a converter also.
That said, I wouldn't spring for a triple disc. I nursed a high mile trans along in my f450, like your doing and I used a single disc, until that trans failed. Then when I put a (used ford reman) in, I put the triple disc in that one and its been in there many years now. It's up to you, but imo, I wouldn't risk a high end converter in an older trans and then trust it (without sending it in, for inspection; cut open/re-welded.) That's the reason I chose the route I did at the time. A triple disc is overkill also for a basic turbo kit idi truck like ours. The great advantage I got the for my trucks, was primarily because they are also super low stall, so they MOVE a heavy load, effortlessly right off the line, without that oem "stuck in the mud" flare feeling. You'll love the thing for sure, but you may want to wait until you spring for a fresh E4OD reman for it.
That rig of yours is worth your purchase price + on an HD e4 reman someday. Don't even think twice when the time comes. She's more than worth it.