ls400 auto output speed sensor?

[snake charmer]

Hi all so I’ve been searching about the output shaft speed sensor and from what I can gather is it needs to be connected for the transmission to shift correctly. How incorrectly will it shift with it disconnected or not installed?
Do’s it need to be connected for off road use?
I am going to be installing this in my rock crawler and need to build an adaptor to fit a L43 “old 4speed” tail housing on now I can set it up with the sensor if it is absolutely needed but would rather not use it to keep the adaptor length/thickness to a minimum.
thanks for the help,

 

[Peewee]

In the stock setup the ecu has 2 speed sensors.
One comes from the dash and goes to the ecu. (SP1)
One comes from the sensor on the back of the gbox (SP2).

Only one of these is needed to shift correctly.
If SP1 is missing the CEL will throw a code.
If SP2 is missing the O/D OFF light will throw a code.

Note: the one on the back of the gear box is NOT the one that is driven by the speedo gear. The speedo gear sensor goes directly to the dash and then gets modified before going to the ecu.

All Toyota dashes since the early 80's have the SP1 output, but I'm not sure about non-Toyota dashes.