99 1.8 Automatic transmission not shifting properly off and on monthly basis Help

[md_medic]

I had problems with the transmission not wanting to go into reverse about 3k miles (117k) after I purchased it. It did not want to go into reverse and would start out in fifth gear from a stop. Frequently It would just go into limp mode at which time I got it to go into reverse. Using my standard scanner I would get codes that would indicate that various gear ratio's were incorrect. Well I changed the fluid and the filter and the problems slowly started to go away. Then at about 121k mile I had similar problems where it was constantly going into limp mode. using my scanner I would clear the OBD code while driving and after about 30 min of driving I would stop having the problems. I kept driving like this for about two weeks and it slowly went away. About 2k miles ago I changed the trans fluid again as part of a couple upgrades I did. Yesterday out of the blue I started having the same problems. I replaced the trans speed sensor today and no change. I recently required a VAG COM and in doing a scan this is what came up:
Chassis Type: 8D - Audi A4/S4/RS4 B5 (1995 > 2001)
Scan: 01 02 03 08 15 16 17 25 35 37 45 55 56 57 67 75 76 77

Mileage: 207110km/128692miles
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Address 01: Engine Labels: 058-907-55x-AEBN.lbl
Part No: 8D0 907 557 P
Component: 1.8L R4/5VT MOTR AT D02
Coding: 06251
Shop #: WSC 06335
VCID: 3D7F311A37404CF6B0B-4B32

1 Fault Found:
18032 - MIL Request Signal Active (Check TCM for errors too!)
P1624 - 35-00 -
Readiness: 0110 0101

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Address 02: Auto Trans Labels: 01V-927-156.lbl
Part No: 8D0 927 156 BN
Component: AG5 01V 1.8l5VT USA 8508
Coding: 00000
Shop #: WSC 00000
VCID: 7AF5FA0666EEBBCED59-4B18

2 Faults Found:
00652 - Gear Monitoring
27-00 - Implausible Signal
00526 - Brake Light Switch-F
27-00 - Implausible Signal

[deft]

I have a 1998 Audi A6 C5 2.8 Quattro, 142kw ACK engine, ZF5HP19FLA transmission.
Now I have this problem. When I drive on cruise speed my car shifts smoothly thru all gears, BUT if am in a hurry, it goes 1-2-3-4 then,if I hold the gas pedal on 2000rpm or low, it shifts smoothly to 5th gear, BUT if I push the 4th gear above 2000rpm, it slips and goes into LIMP mode....until OFF & ON.
After driving like for about two years I decided to throw in another transmission and behold...exactly the same problem as the former.
I have tried another TCM on it....same issue.
VCDS suggested changing the Multifunction switch(F125), that I have not done.