It's the same place for both transmissions. It's located on the top, rear of the transmission.

 

Ok, that's good input Mark & here is a pictorial look at where it is located on the drivers side of the 5R55E tranny case & what it's fastened in with, along with the fastener torque value. http://repairguide.autozone.com/znet...3f80e43254.gif

 

I think I have the right sensor located....it's a 4 speed auto, and the sensor is on the top of the tranny near the end of the tranny...I was thinking the same thing Dremel tool and cut a slot,
I almost have to one by one, take everything in the circuit and have them tested, then buy the appropriate one...depending on which it is ...the price could be as low as $15 or well over $150

 

I use these Diamond Rotary Cutting Discs 5 Pc Harbor Freight diamond cutting wheels for my Dremel & they'll slot hardened bolt heads too.

 

OK...I know where it is...What I need to know now is how many sensors in the Output Shaft Speed Sensor Circuit? The possibility of me being lucky enuff to pull the right one on first attempt is so small...I'd stand a better chance being elected Pope...

 

The pictorial link I posted shows 1 speed sensor in the output shaft speed sensor circuit. First remove its electrical connector & check its windings for continuity. It looks like my rear ABS speed sensor & if so, it'll measure something like 1.9K ohms resistance, unless the winding is faulty/open circuit/no reading.

 

There is exactly one output shaft speed sensor. It's the only sensor on that circuit.

 

OK...got all the info...now I gotta get it out and check it on a multi meter...but if it is not defective...where do I go next with the PO720 code?
Just want as much info about what to check next as I can come up with before I tear into it...

 

You should be able to check the sensor windings for continuity before removing it. If its ok, no need to remove. If it checks ok, inspect the electrical connector contacts for damage or corrosion & the wiring for damage. If ok, go to the computer firewall electrical connector & check the wiring run for end to end continuity. If ok, suspect the computer contacts, or the computer & let us know what you find.

 

Man....this starting to get complicated.
Biggest hold up right now is getting started...I am in pretty rough shape to be crawling up under cats and trucks.
But I will get after it...
Thanks for the info about checking them before taking them out. I think I can do that pretty quick in the morning...then I can have the new parts in the afternoon ready to install

 

OK, lets think about this some more.
First disconnect the battery B- cable.
Then disconnect the firewall computer electrical connector & measure across the two output shaft speed sensor wires there, (they'll have the same color code & connector wiring position as the wiring link I posted), to see if you have speed sensor circuit continuity.
If your tranny output shaft speed sensor sensing coil is like my rear ABS speed sensor/has about the same number of turns in it's coil, you should measure about 1.9K ohms resistance across those two wires at the firewall computer electrical connector.

Doing it this way you'd not have to get under the vehicle, nor have to remove the speed sensor electrical connector, or the speed sensor for testing, as you'd be accessing the speed sensor through it's wiring run, thus checking the speed sensor & its two wires at the same time. If they check out, suspect the computer firewall socket connectors, or the computer.

If you measure open circuit at the firewall computer connector, Then you'd have to go underneath to disconnect the speed sensor electrical connector to check the speed sensor for an open circuit.

If The speed sensor checks out & you come to suspect the sensor wiring run is open circuit, you could use a piece of wire to short across the tranny end of the output shaft speed sensor electrical connector, then go to the firewall end of the computer electrical connector, disconnect it & use your multimeter on the ohms scale to measure continuity between those two wires, to see if one is broken. If one wire is broken you'll read infinite resistance/open circuit/no continuity.

Then to determine which wire run is bad, you could rig a long test wire to one of your multimeter probes & do a end to end continuity test on each wire.
Or you could connect/jumper one speed sensor wire to a unpainted clean ground spot on the tranny case & measure between a unpainted body, or engine, or tranny case bare spot & the speed sensor wire at the computer electrical connector end & that way the ground connection would act as a test/long jumper wire, for the wire run end to end continuity test.
If both wire runs & the speed sensor check out & you don't see any corrosion or pin/socket problems on the speed sensor end, or the firewall computer electrical connector end, suspect a computer end problem.

A bunch of test thoughts for consideration, let us know what you find. Right now my bet is that the output shaft speed sensor coil is open circuit.