XR gears in an IMCO case , upper gears pitted and started going away . But that's with about 850 HP

Couple of uppers for me
lowers are all good

Upper gear set and top cap - HP525

funny, I had 2 600hp behind trs in a heavy old formula never had a problem

Broken both top and bottom but def. 3 or 4 to 1 top over bottom.

I've replaced several upper gear sets just due to normal wear. I think someone already touched on the fact that it is a marketing item for Merc rather than quality control. No diff than GM installing non-grease able fittings from the factory so you have to replace them.

Does it matter which direction the drive is rotating. I ask this to wonder if the load is on the top cap or the floor of the case.

Funny that back in 1988-1991 era, you had a couple options when choosing power in most offshore boats.
(Black Mercruisers)
454/330HP=Bravo one
454/365HP=Bravo one
502/390HP=Bravo one

(Mercury High Performance)
454/420HP=TRS
502/465HP=TRS

Anything bigger than that you got SSM IIIA, V, and eventually 6. How about the early 525SC hooked to a SSM IIIA? Talk about reliable!!! A drive rated for 750HP couple to a 490HP engine.....its like a XR behind a 454/310HP MPI.

At that time, you could not even get a 454/420HP Merc Hi-perf engine coupled to a Bravo from the factory. So, I would put a TRS/72C up against a Bravo, or bravo XR any day. Now if they had kept the TRS, and made some shorty lowers for them, that would have been cool.

yes it does, the left hand drive pushes up on the top cap under power and, in my case, stretches the bolts allowing the tolerances to go out.

sorry, but this poll is like asking everyone who attends an aa meeting "raise your hands if you like to drink"! we all know that the bravos break and break yet you keep going back to the fountain for another desperate cure. why not start a poll on the alternatives to bravos rather than the next drug for bravo owners? the reason everyone is hooked on these things is that so many mechanics are making their living off repairing them to the extent it would be finical suicide to recommend or have the customers change to anything else.