There should be a zert to grease the gimbal bearing,(on back of transome should be on right side) zerts on engine coupler(those are a pain to get to but must be done) and then on u-joints but you have to pull drive to do that. Even if it doesnt cure the noise still needs to be done for routine mantainence

What does it sound like.
If it is a rattle at the rear of the motor it could be the metal flappers in the Y pipe going down the back of the motor.
If it is a U joint or gimbal bearing it will get worse when the drive is turned hard in either direction.

Ya. I only said that cause from my experience if the upper goes the fragments usually end up in the lower. Change the fluid and see how much metal comes out. align the drive and grease all fittings.... Have fun! Make your way down here before winter...

Where are the zerts on the coupler located? I've got 496hos with X's. I usually had someone do the service, but this year I did it myself.

Zerk fittings are on the hub on the back of the coupler, where the input shaft goes into the coupler. They should be 90* fittings, two of them, 180* apart. You may have to roll the motor a bit to see them and get to them.. A couple of shots of Spline Grease goes there.
The gimbal bearing gets grease, not sure what is spec'd out. And the Ujoints use Ujoint grease. But any good quality grease is better than no grease.. :)

Dick

Well, took the boat to the local marina today, gimble bearing was almost gone, one u-joint was bad, the other one borderline. I would have liked to do it myself but time and my non-experience in outdrives says otherwise if I want to boat the remainder of the season. I will probably do the other one myself over the winter if I can find someone to help that has done it before, since if one was bad, I figure the other (same hours) probably isnt far behind. Good thing I took it in because they said the gimble bearing was close to coming apart and causing major damage. BTW anyone know offhand how much parts are, just wondering how much I would have saved by doing it myself.

U probably would have saved alot of money but like you said season would have been over. In MI season cant be that long before it starts getting cold

Definately, could be nice till October or could be done in a couple weeks, thats MI for ya.

I was thinking it would be a universal bearing. When they go, you can feel the floor vibration at part throttle and it makes you think something is really wrong. Other vibration stuff I dealt with was clutch shuttling since the shifter was out of adjustment, that mistake costed me a drive...can you say friction welding the clutch pack?!!!!

A good invoice should have the parts listed by part # and priced out. Chances are they are charging full merc retail on parts. You could maybe save 10% on the parts at www.mercruiserparts.com