I am at a loss. I got a check engine light, ran the codes and got P0716 - Input speed sensor. So Advance Auto looks up the information and there are 2 sensors. Front input sensor and rear input sensor. So I located the rear sensor on the passenger side right above the oil filter. Changed it out no problem. I looked at the other new sensor and it appears to either mount in a dry location or possibly inside the transmission, due to the fact that it has no seal on the sensor. Can anyone help me out to locate this dang sensor? I am at a standstill until I can find it.

There should be a input speed sensor assembly on the case cover at the front. It'* hel in place with a clip.

I must really be missing it then because the only other electrical I see is a large round connector on the very top under the airbox hose. The sensor has a connection for only 2 wires. The electrical connection looks exactly the same on both sensors, just a simply clip in place plug.

In looking it up.. that'* the ISS or input shaft speed sensor. The good news is I know where it is, the bad news is I know where it is.

It'* inside the transmission. On the drive sprocket is a metal wheel with slots that passes in front of the ISS. A couple of the things I noted said to check the wiring at the trans. This is the wiring that goes into the trans below the throttle body.

So is there any breakdown of how to replace it? I am not concerned about pulling the pan and such, but are we talking pulling the valve body or any other major parts? Does anyone have a service manual that could help with the procedure?
I checked the plug directly under the air intake tube and nothing is chaffed or looks out of place. Any idea what to exactly look for? It doesn't seem loose or anything.

Thanks for the help.

I've actually lent out my manual currently. Found it on ebay though under ATSG 4T65E. Great book for about $13.

You'll be looking at getting the trans out enough to pull the side cover, valve body, pump and then the reluctor/sensor are right by the chains and drive gear.

So getting access is just a matter of removing the side cover and is the rest pretty straight forward? No fluid drain? No axle pulls? Not really worried about tackling such a job as I have been doing my own mechanic work for 20 years, I just don't like surprises.
On another note, the speedo has never acted up and I keep reading that the speedo should stop responding when the transmission acts up. There is reference to the TPS may be causing the transmission issues. The only thing is that I got a code P0716 and I replaced the output speed sensor and had the code erased. The transmission has acted up again but no check engine light has come back on. I am going to take it back by the parts store and have the codes checked again.
I searched ebay and found the following link, but not sure if it is worth the $35.
eBay Motors: Pontiac Bonneville Service Repair Manual 02 03 04 05 (item 130299401018 end time Apr-15-09 14:44:33 PDT)
I also found a link using what you specified and found:
eBay Motors: ATSG TECH MANUAL 4T65E 4T65-E 1997-ON GM ELECTRONIC (item 350161644639 end time May-03-09 18:53:05 PDT)
I have a Haynes manual which is great for general info, not so great for precise instructions. It doesn't even mention the Input speed sensor.

If you can get your hands on a Factory Service Manual, that would be my recommednation. They are not cheap, but the first time you pull it out to do your own work, they have paid for themselve.

Thought I may have mentioned it and don't see it. Hate it when I think things and don't post them.

To get the side cover off, the trans needs to be out of the vehicle.

Well crap, looks like its selling time. I will check the codes again and if it shows up then I may just sell it or trade it off. I have no desire to pull the transmission or pay to have it done. Thanks for the info.