Can somebody help looking for a procedure on how to change broke a few teeth on the upper gear set the gear below the clutch do I change them all or just the one that is chipped also thx

Change the set.

You'll want to disassemble the lower and clean out the fragments that migrated south

You cant simply change the gears. The new set must be set up correctly. The job requires a few special tools from Merc. Not particularly difficult to do, just needs to be done right. I agree, the lower needs to be taken apart to be checked and cleaned out of debris.