Problem Changing From 1st To 2nd

[skippy 2]

I know this subject has been mentioned several times over and I have looked at most. The problem I have is sometimes not all the time the gear will not change from 1st to 2nd the revs reach 4000 so I take my foot off the pedal as I don't want to strain the poor gal and this normally changes it to 2nd. I have checked the gear oil level by the way it is described on this forum but not with a vagcom. There seems to be enough oil in it as it came out of the overflow. I have had a word with a gearbox specialist not necassarily galaxy and his thought was not the gearbox but the Throttle Position Sensor He said that the sensor works out where the throttle is before changing gear can anyone advise on this and where this sensor is and can it be changed. What are your thoughts please as this problem is bugging me.