electric connections on the allision

[DATSBAD]

i see that there are 3 plugs on the trans , one on the pass side , and two plugs on the drivers side rear at the black box on it . can someone tell me what these are ?

[77TransAm]

The plug above the torque converter is the input speed sensor.
The plug above the left PTO cover is the turbine speed sensor.
The plug on the rear cover is the output speed sensor. (This is found on the transfer case on 4WD models.)
The combination of these three can tell the TCM whether the trans is slipping at any time and allow it to set an incorrect ratio code.
The NSBU, as has been described in great detail on this site, is on the left side of the trans above the oil pan near the rear. It tells the TCM which range has been selected. A search of the archives here for "NSBU" will bring you more information than you could ever want about this particular piece of hardware.
The 20-wire connector on the right rear of the trans is for the internal wiring harness, which connects to the 6 or 7 (depending on transmission vintage) solenoids in the valve body and the Pressure Switch Manifold on the valve body. The TCM tells the solenoids when to operate, and the PSM verifies for the TCM that they have activated and that a valve has stroked.

[DATSBAD]

which one plug or wire controls the odometer reading ?

[77TransAm]

The output speed sensor.

[DATSBAD]

wonder what would happen if it became unplugged?

[77TransAm]

You'd start setting codes in the TCM like output speed sensor, incorrect ratio, things like that. For fun, I just went and unhooked the output speed sensor on a truck. It worked fine in Reverse, but I got about 10 feet forward in Drive and it defaulted to Neutral. I shifted to Neutral, back to Drive, 10 more feet and another default to Neutral. It did not set an SES light, but it did store codes.

[DATSBAD]

yep , the same for me . give me your email i want to talk to you off the board . thanks or email me , jasmhuber@earthlink.net