My peugeot 307 gear linkage counter balance

2nd 4th and reverse gear means that you need to pull the gear knob (in passenger compartment) backwards which inversly push the gearbox's gear-link (on gearbox) upwards. 1st 3rd and 5th gear pulls the gear-link downwards (which in your case works fine). Pls check your linkage cable fittment at gearbox in engine bay. There are two cable holders which are connected to gearbox. First is at the very end of cable which is small plastic ball connected to the gear-link.
The second one is Cable retainer socket which serves to stop moving cable's plastic covering body. This is fitted to gearbox's plastic cup holder ( hint; cup holder contains two half circled cuts) attached to gearbox metal body with three bolts. Just check the cable at this point and possibly cable's plastic bush restrainer is slipped out of half-cut circle-holder. You must push/fit in correctly the cable round bush holder in the half-circled cut to restrain cable's plastic body movement.

I can't change into 2nd,4th and reverse gears. i think its a gear lever cable not sure doe any ideas?