Just pulled my drive off (2002 XZ) and separated the upper and lower. Found a snapped vertical shaft and the upper gears are seized.

This is on a stock 500 efi with 185 hours on the clock. I have owned it for the last 55 hours and it has been babied for those hours. Bad part is this is the second time the drive has blown up!
It was rebuilt right before I bought the boat. You would think that a manufacturer would manufacture a product that would at least stand up to the stock power it is putting in front of the drive!

Call me crazy but it would seem to me that MERCURY MARINE DRIVES SUCK!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!

Looking for suggestions on what to replace this with. I have a Lavey 29. It does make sense to me to keep buying 6k-9k drives every 90 hours.

sorry to hear this, merc has always been so good for me over the last 42 years of boating, sorry to see this kind of stuff happen. maybe the rebuilder made a mistake! what type of oil do you use? do you come out of the water much? I have run bravo drives for thirteen years, with merc oil, and over 1,000 HP each with no problems. I would not blame the drive with only stock power. IMO something had to be a muck at the rebuild.

I don't have any suggestions other that the usual aftermarket drives, good luck

I raced the snot out of my F1 boat and never had a drive failure. Sounds like abuse or it wasn't rebuilt properly.

320 hrs, twin '04 XZs with 525s and although I don't/wouldn't holeshot cause props will blowout, I do spend significant time out of the water and based on the chirps my throttling is not 1st class.

Gaz do you have any type of drive showers? I believe in them the upper gears have no chance without some form of cooling. Just an obsrvation based on years of boating.

Good point...drive showers from day one here

Could have been abuse before the first time it was rebuilt. I bought the the boat at 130 hours and it had already been rebuilt once. I changed the drive fluid twice since I have owned it with Merc fluid. Drive has never left the water except on a trailer. Just curious at 1000 hp what drive are you running and how many hours before the top gears are replaced?

Yes, had a drive shower when I bought it. Not sure of the brand.

Sorry to hear about your drive problems. Lots of us have been in your shoes.

You could try having a shop "put it together better" like Mr. gadgets, or Max Machine worx, or Bravo shop, or all american drive service, etc. But theres no magic ferry dust.

You could run Amsoil severe gear oil, Bravo shop oil, Royal purple, redline, etc and hope it helps.

You could waste money on upgrade parts but I would save my money for a spare drive, and/or rebuilds.

Could upgrade to a IMCO SCX, BMAX, Konrad, Arneson, XPower, etc,

Do you have any dreams of upgrading boats?

Good luck

I have a 272 Baja with over 1000 hp, has over 300+ hours on a set of xr gears with 750/950 and then 1050 hp that still look like new in the upper. Had them cryoed and iso rem'd early on and I am in it the drive 1-2 times a year changing bearings, inspecting it and changing lower gears (they fall apart every 30-50 hours -BUT I usually change them before anything else gets hurt) so the upper gears can last. I also have all the Max worx stuff though too like the steel tower and billet cap etc, Smitty
I would say somebody cut corners or didin't know what they were doing when they were in the drive last time, whatkinda prop center line and are you running a 5 blade, I hear of alot more destruction with 5 blades.