2004 blobeye 5 speed gearbox speed sensor location

Hi all hope everyone is well I recently brought a blobeye impreza wrx wagon with standard 5 speed manual with what I think is a gearbox speed sensor fault car won't rev over 4500 - 5000rpm and speedo not working both signs of speed sensor fault only problem is I can't find the sensor thought it was on top of the gearbox under the intercooler and just in front of the gearbox dipstick but nothing I can't even see any wires going to the top of box can anyone help would be much appreciated many thanks Andy