2004 Merc 350mag/mpi Bravo1, 154 hours. Drive goes up/out fast and smooth, pump sounds OK. Will not go down/in, unless under load, and pump sounds weird. When I am running, it goes down fine. Plenty of fluid in reservoir.

I am guessing that the down/in pressure relief “green” valve is the problem. I do not have access to a hydraulic test gauge.

Does it sound like I am on the right track?
Is this something better left to a Merc Tech?

Could be a messed up seal in the rams as well. I would disconnect them at the back of the drive and see if they move together. I had the same issue and it was a bad ram.

So have I, on two different boats.

SEAL IN RAM ( O- RING ) !!!!!!!!!

Its bypassing !!