4.0 speed sensor VSS

I am installing a 4.0 in a 87 wrangler the motor is a 93 what can you guys tell me about the vss sensor and keeping my mechanical speedometer working. is the sensor on the outside of the transfercase? any imformation would be great.

How much of this thing are you installing? VSS/ Speed sensor will be in the tailshaft of the t-case...and if it comes down to it, I have a speedo adapter out of a 242, 94,92,well some year...that you could put a speedo cable on...and I am sure it would work on a 231...at least the one out of my 96 231 worked in the 242...