[agfours]

Problem solved!!!!! Just wanted to provide a little closure for future generations that might encounter this same issue....

Did a lot of deep research tonight on the forum after reconfirming my earlier findings regarding the electrics and path of logic...took me deeper into examining the posts related to the actual magnetic carrier ring that is attached to the diff that sends magnetic pulses to the sender on the side of the tranny. I found a deep post that someone had found that the replacement senders from VDO are a little different in spec than one that you might get from Porsche. Evidently the newer ones sit deeper into the recess or somehow don't make good pickup from the disc on the diff. The poster had used a piece of heater hose between the diff and the sending unit and got good results, albeit a little less Germanic than intended from the factory.

Well, I decided to try the same idea. I found a little nylon bushing that perfectly fit the diameter of the sending unit where the unit goes into the hole in the tranny. I slipped it over the o-ring to act as a washer about a quarter of an inch thick between the sending unit and the body of the tranny. Worked like a charm. Hooked up the volt meter to the spades in the access tunnel inside the car and started to get a signal when I spun the wheel hub!!! Road test confirmed proper operation, and speed registering correctly per GPS app on my phone.

Let me tell you, again, just a testament to the power of this board and the depth of resource it is! Who knows how much that would have cost in diagnosis at a shop...

Interesting footnote here is that my expert wrench here in town said "probably the sending unit...those are the case 90% of the time...". Well, yes and no. I went back and tested the original sending unit, the first replacement, and the 2nd replacement now in the car, and all worked fine using a volt meter and a hand held magnet waved over the sending unit...just use ohm setting and the circuit will close (ohm out) across the two wires when the magnet passes over the sensor....shoulda researched that to find that test first time around I guess...20/20...

Guess I'll see if I can return one of these sending units....

Thanks to Porwolf for the reply as well!