There's a couple of other vortec swaps documented in the 80 section and one did use the 60 t-case. It can be done, it's just a matter of selecting the correct adapter from advanced adapters.
The GM VSS would normally come with the donor 4l60e or 4l80e (and variants) transmissions. GM puts the speed sensor in the tail housing so that it senses the output shaft speed of the transmission. GM then uses a sensor in the transfer case that tells the ECM when low range is selected so that it knows to alter the shifter pattern. Toyota does the exact same thing. In reality - toyota uses a speed sensor in the transmission and another in the t-case. The transmission speed sensor tells the TCU (trans control computer) the output shaft speed, and the t-case sensor sends it's signal to the speedometer. When you go to low range, there's a switch on the selector shaft inside the t-case that tells the TCU that the truck is in low range. This is why you see people doing the 'pin 7 mod' in the 80 series when they add a CDL switch in the '93 and later trucks.
For the purpose of the swap to a 4Lx0, we have to retain the GM speed sensor so that the GM ECU knows how to shift the transmission. It plays no part in sending any signal to the speedometer. This is handled by the stock toyota speed sensor that is retained on the t-case. The GM sensor swaps over to the AA adapter and it's function is retained.
Now here's where it gets interesting. when you go to low range, the GM ECU does have an input wire for the low range signal so that just like the toyota, it will also alter the shift pattern to better suite the low range gearing. Now, you have to account for the difference in the low range gearing. IIRC, most of the GM 4wd trucks use a 2.6ish low range gear and the 80 series is very close to this at 2.49. They are pretty close so there is no real need to change the programming inside the GM ECU to account for this. Obviously, it you went to an Orion t-case with a deeper low range, you might have to fiddle with it a little. So bottom line, the toyota low range sensor will substitute for the GM low range sensor and the GM ECU will think it's driving a stock GM truck.
Finally, in regards to the 60 series t-case, you shouldn't have any issues with the VSS. The GM sensor will be in the AA adapter, and the 60 series case should accept the 80 series VSS as a swap over. It's interesting how much interchangeability there is between the 80 series themselves, and also between different makes.
I do indeed plan on figuring out an adapter harness and will make some on the side. The issue is that once I was given a print out of the '93/'94 EWD and compared it to the '96 EWD, there are some differences in the ECU connectors. primarily there is an extra connector (IH3) that exists in the earlier trucks that does not exist in the later trucks. This connector houses all of the trans ECU wires. The '93/'94 trucks use an external trans ECU to operate the A442 and the later trucks have the engine ECU controlling the A340 so some wiring is eliminated in the harness for the later trucks. Regardless, it would take someone wanting to do the swap to forward their engine harness to me for modification. More to follow once I get deeper into this.
