My car e92 323i (2.5L N52 and GM Gearbox) has been plagued with a weird issue for a while now. It randomly happens, mostly at low gears which I would assume gear 1 shifting to 2 at around 3000rpm. My usual experience would be, the car moves till it reaches above mentioned and the gearbox would act up in a way where it struggles to lock/shift into the next gear. When this happens, rev needle keeps fluctuating around 3k rpm till it catches on to the next gear.. However it’s worth noting that this usually happens only when i accelerate after going through a bump or after a hard break. It also occurred randomly when coming out of junctions which is pretty dangerous as the car would just remain ‘powerless/hunting for the right gear’ for a few seconds. Also happened a few times during slow traffic and when i accelerate to take over some cars. I have taken a video to explain and u can actually hear how the engine/drivetrain and rev needle reacts. This was taken when i accelerated after crossing a small bump.
Ive sent it to a local expert workshop but there were no codes. Cleaned my vanos but doesnt seem to work. Gearbox oil, coils checked out okay. They told me that it would be better to change a gearbox as it would be difficult to figure out whats wrong as there were no codes. Unlike the zf gearboxes, i am not experiencing the usual hard shifts/shudders when coming to a stop. There are times where i can feel a harsh shift though when gears are changing, as if there's a light 'klunking sound'. Hopefully someone can guide me in the right direction. Here is the link to the vid:
When this happened, my foot was still on the pedal. Rev needle stutters and the car loses power (slightly jerks) till it catches on the gear again. What i could not understand is it hardly happens on a straight road.