It's been a while since my last post. I needed to take a break from the issue and clear my head. Here's what I've done since my last post. I went over the speed sensors, wheel bearings and rings a second time with no issues found. I took it to an indy transmission guy with no experience with ZF units. He said right at the first hard shift, this isn't a mechanical issue. In his opinion, it's electrical. Take that for what it's worth. This coming week I have an appointment at a Jag dealer to have the transmission flashed and adaptions reset. It's the last thing I can think of. I'll have them check the connectors and confirm the proper fluid level before the service. Right now, I'm driving the car without faults. I start out in manual 3 and shift into 4th with no throttle. The only time it'll fault, is when I shift into 4th going up an incline. Still baffled by all this. Hopefully the dealer can sort it out.

 

Good luck and keep us posted....

 

Read thru the entire thread and did not see if you replaced the connector sleeve. I saw where you did check the connections. I ask this as when I changed my fluid I replaced the sleeve
and did not get it pushed in all the way. This after driving a bit started to throw codes. I removed the plug and found hydraulic fluid on it, Cleaned it and it would be fine for about a month.
I finally took it to a shop to have the sleeve checked and sure enough it wasn't pushed in all the way. Have not had a problem since.