Need help on upper...What is the deal on the service bulletin for the new upper gear set. Can the new style gear set be used with an older housing...it is a 98 drive and I have talked with a few people that say you cant use the upper housing with a new gear set ....something along the lines of a service bulletin ..any help would be appreciated

Yes you can do it....there's a kit to do it....have done it a couple of times.

here's the bulletin
https://www.mercruiserparts.com/bull...2001/EN_17.PDF