ok, just to give some feedback.

the new gear ring was shattered again, the bendix was not matching correctly the gear so the ring was destroyed, we custom made a new ring (cause linde original parts are expensive and have long delivery times) and fixed the bendix lenght, now it grabs the ring at a smooth path, we calibrated the speed sensor at 1.5 mm
and voila!!

the truck is running nice and quiet, better than the other one.

we also saw that old ring was wrong seated in the flywheel generating a lot of vibration.

so guys, remember, when t248 is present. check

1. RPM sensor Wiring & harness
2. RPM sensor, (remove and clean from steel garbage, calibrate to 1.5 mm aprox)
3. gear ring's tooth
4. correct gear ring assembly in flywheel and balancing.

i hope this is helpfull