Transmission puzzle
 

Hi guys hoping someone can point me in the right direction.
Car is 1781cc petrol auto dmu gearbox think its 01n.
Before changing the transmission atf and filter the car was reluctant to engage the torque converter clutch tcc in 4th gear. Accelerate in 3rd to over 50mph would get it to engage when switched into drive- maybe a scream but clunk and bingo would drive on motorway for ever it seems.
Now after changing atf and filter (correct spec) tcc will not engage in 4th gear at all.
symptoms - seems like the torque converter can freewheel. If i take my foot off the throttle in 4th engine revs go to tickover but the speed can accelerate downhill !. If I do the same in third gear at high revs I get engine braking. In D in 4th the power is delivered by the torque converter fluid coupling not direct drive at all speeds.
Vag com code 01192 is thrown possible causes are suggested to be ttc malfunction,valve n94 defective,electric connections.

My puzzle is the tcc will work in other gears but not 4th - maybe I am wrong but the tcc seems ok mechanically so what other inputs code cause it to behave like this ? From reading 01m service manual (cannot find 01n) n94 solenoid is used in third and fourth gears. The electrical connections function to work n94 solenoid as there are no problems in 3rd gear. Anyone have a clue please.

Update - not only do I have a tcc problem but a slipping clutch problem. By that I mean at around 40mph to 50mph 4th gear slipping seems to be very responsive to the throttle load. I feather the throttle to stop it. The interesting thing I found today on a 200 mile drive is that once over 60mph this 4th gear slipping disappears making me think it may be a ATF pressure problem caused by restricted valve or pathway taking time to generate enough oil and pressure to apply the gearbox clutch properly in 4th. Whether this affects the TCC is a puzzle, Tcc in 4th did not engage today .