Renault Megane automatic transmission problem

Hi,

Patient is Renault Megane Coupe 1.6 Automatic -98.

Before there was severe problem in transmission that caused slipping on
gears 1 and 2. Some clutchdisc was broken that caused it. Thats now
fixed and transmission works fine except one small but irritating
problem.

When driving about 70 to 80kmh with 4th gear on and starts accelarate so
that 4th gear stays on, the transmission error - indicator lights up.
This is not the case when motor and transmissions are cold, but when
they are warm you can repeat that as many time as you want.

Error code has been read and it says that error is in speed sensor. It
has been changed as is pressure sensor and magneticvalvepack. No help
what so ever. Error code keeps coming. Wires has been check and they
_should_ be fine.Pretty much only thing that hasn't been changed is the
computer box.

I asked that computer box from another repairshop and they said they
have had one another similar case like mine and only(?) solution was to
change whole transmission! That sounds 'a bit' too radical now that
current transmission has been repaired for a great amount of euros. They
also said that they have never changed computer box to Renault and
didn't suspect that it could cause the problem.

Does anybody know what could cause that behaviour of the transmission
and is there a fix for it another than sending it to back to factory?

Thanks.

--
"Life is a bitch, but she's _my_ bitch."