Strange transmission problem...

[JAD]

OK...about 6 months ago I had a problem with the transmission in my 1999 ML430. The car would do one of several things. From a stoplight the car would feel like it was starting in 3rd or 4th gear somtimes, no matter how hard I hit the throttle. Or the car would shift alright up until 3rd gear, but not go into 4th. Or on the highway at highway speed, the car would not kick down. No slippage of gears ect though. So indy replaced the AT Adapter Plug A 203 540 02 53 as there was some fluid in there. Tranny has been fine for 6 months and 5,000 miles.
Now some of the same symptoms are re-appearing. Codes the car has thrown are:
092 TEST FAULT (IGNORE) - 108 SPEED SENSOR 2 IS SPORADICALLY FAULTY --- 110 THE COMPARISON OF SPEED SENSOR 2 AND 3 IS SPORADICADICALLY IMPLAUSIBLE

Any ideas? The indy mechanic is guessing the conductor plate?? No fluid in the new adapter plug, he checked. Has anyone had this problem before?