You looking maybe for something like an “electronic ratio adapter” ? Those will modify your PPM (PulsePer Mile) to match what your ECU expects. Chris at UJOINT is one place that has those ready to go...
To confirm, your current output shaft has no ring to be picked up by an OSS? You mentioned the “housing” doesn’t have it, but it looks like the tail housing has an OSS sensor on top?
I’m having a BTS 4r100 installed (never heard back from JW after emails and a call, but BTS was right on it)
In my case, i originally had a quigley set up using a 2wd 4r100 configuration and then switched from a BW1356 to an Atlas2, that required changing out the 2wd tail housing to a non OSS tail housing and then ended up grabbing the VSS signal from the atlas tcase using a 35 tooth gear. With this new tranny though, Brian set it up with a 2wd output shaft (longer than 4wd shaft so everything matches physically in current set up) with a 21 tooth gear and a tail housing with an OSS port. This will let me hook up an ERA to dial in my shift points while running 35’s with 4:56 gears. If I was starting from scratch, I would have gone full 4x4 stock set up on the tranny (shorter output shaft) but with current set up, I would have had to also change both drive shaft lengths.