Help with 355 tranny

[BLKay]

Hello. My 355 tranny slips and revs out only after running for 15 minutes. 2 questions.

1. It was suggested it may be overheating. Could this be the cause? My next run I’ll put a laser temp huge on it and compare with the other. What should the temp be?
2. If not, tranny removal. Can this be done in the water and what are the instructions to do so? I’m concerned about the prop shaft and have been told several different things, including my boat might sink. It has drip less seals and the 355 has long shafts supported by a bearing support below the boat.

I’d like to know for sure and not just suggestions please. Also one of the Hull valves is stuck open and should be changed on my next haul out.

[tomschauer]

First verify the fluid is full and clean. If it is "burnt" you most likely lost some clutches and need repair. If the fluid is full and clean I would check the shift linkage at the transmission to make sure it is engaging fully into forward and reverse.

If you need to pull it, it can be done in the water if needed. Put a large clamp on the propshaft so it can only move an inch or two to gain clearance from the tranny. Even if you don't do this, the rudder will stop the propshaft from "falling out of the boat" and sinking the boat.
You also need to support the back of the engine before unbolting the tranny.

Parts are readily available and relatively inexpensive for rebuilding the BW velvet drives.

[RGrew176]

When they rebuilt my port side transmission a few years ago it was easier for them to pull both the engine and transmission together.

[chpsk8]

I just had the starboard trans out of my boat this spring. It was done out of the water, but could have easily been done in the water. Full rebuild with seals and clutches/etc was $1800 plus labor to pull and put it back in.
They did have to lift one side of the engine to get the trans out, so the engine mount will need to be disconnected. They also removed some cooling lines.
I would suggest the first thing you do is pull the oil out and put new fluid in. Let it swirl around in there for a bit, then do it again. If it's losing thrust after time it could be the oil is either old, or wrong. Could be your clutch is starting to slip and is worn. How many hours do you have on the motors?

[AnamCara]

Its easier to pull the engine to get the trans off. I did it last winter using an aluminum gantry set up in the cabin.