Several thousand dollar lesson learned
 

Last year I had my starboard IMCO rebuilt because it let loose after minimal use. I bought the boat in Feb of 2015 and have receipts of both drives being rebuilt in the fall of 2014, prior to my purchase. I only had about 6 hours or so on it before it locked up. Not sure how much driving was done from the previous fall prior to my purchase. Regardless, I bought all new internals, gears, bearings, races, shafts etc. to rebuild 2016 Labor Day weekend. Well, that same drive let loose again last weekend. Both times, the shifter pin was bent. The first time, I didn't care much about root cause, I just wanted back on the water because the boat was still new to me. This time, with the same symptoms, we really started thinking about what would cause this. Well, I guess sometime in the past this drive blew and "tweaked" the upper housing, casing. So now the cone clutch, gears etc. don't align perfectly with the lower and upper "chimneys", bearings, so even though it all goes back together, it wears at an exponential rate. So I'm now buying a new housing from IMCO that will be pure and straight. Just wanted to post this in case any of you all have had drives expire prematurely and wondered why. Knowing the cause initially can save thousands, wish I wouldn't have been so eager on round 1.

A wise man learns from the mistakes of others. A good man posts his mistakes so others can become wise men. Thank you.

Who rebuilt the drive and didn't catch that problem with the case?

My Dad's mechanic rebuilt the upper (Parker Marine, LOTO), The Bravo Shop rebuilt the lower. The upper is the issue. You can not physically see the misalignment in the upper case. After discussions with IMCO on the two failures they stated that there had to be some misalignment with the upper casing to bend the shift pin both times and the second time it wiped out the upper top cap bearing race (as in sheered it off), no visible damage to the gears themselves.

"Shift pin".... sounds like what you're describing is the clutch shaft ( the shaft the cone rides on, rides in a bearing in the lower case tower and a bearing in the top cap....is this what you're referring to ?....there is a "shift" shaft in the upper, but all it does is move the shift fork

The "shift" shaft in the upper is what I'm referring to that bent both times. Not the cone clutch shaft. The upper casing is what I ended up replacing along with all the internals.