help needed with 904

Yes, it's a new day.
Up and drinking coffee.
questions of the day? Should I pull the other one apart? Really LOL is just dirty LOL I'm up to my neck with cleaning! After that 318 build I'm getting burned out on it a little. course unknown condition also, but from the neglected condition of the motor and the sheet of gray jelly hanging off of the filter? Who knows...
Thinking out loud again: (1 or 2 grains of salt may be necessary)
What the heck did this last "speed shop" do to this thing from stock? What kind of shift kit? Good, bad, cheap, expensive, and most importantly is it worth a crap?
So, do I rob the valve body off the yucky one and will it fit ? And if not ?
could rob the 1-2 clutch packs out of yt (yucky tranny)? Clean and cross fingers? And blow the doors off some ricers with a pink $50 Craigslist 318!

That burned stuff is common as can be (especially without a TP hooked up) and is still what it looks like happened.
The band is even burned, which leads me to believe it was running on low line pressure (everything was slipping)

I think you should continue on the one you have as the rebuild kit has everything needed to replace the burned up stuff except for the inner and outer most thick steel plates in the clutchpacks. (Called pressure plates)
These are the ones against the drum piston, and under the big snap rings that hold the packs in.
I should see those, and I can tell you if they can be run.
Also at some point we need to get into the valve body and see what's been modified, and then you can make the decision on swapping parts with the other trans.
Who knows, you might end up rebuilding that as well.:D