Transmission problem

alexm · 07-23-2012, 02:58 PM

After hitting a rock, damaged struts, shafts and props.
Everything has been changed for a new ones. What would be a symptom of coupler/transmission damage?
How can one distinguish between the misalignment of the shafts and coupler/transmission damage?

Marmot · 07-23-2012, 03:38 PM

Misalignment can lead to coupling/transmisson damage.

If you are afloat, unbolt the shaft coupling and check the alignment with the boat loaded the way it normally runs.

Check the gearbox oil screen for wear metal and have a look at the oil. If the oil looks good have it tested.

What symptoms are you having that lead to this question?

alexm · 07-23-2012, 08:22 PM

My shop replaced the running gear, then they take the boat for a sea trial and decided that probably there is a coupler or transmission problem- they could hear some noise, which appear while they were going, forward and reverse.
They did not do realignment. The oil looked OK.
Just wondering, how can they say this is not a misalingment but rather coupler/ transmission issue?
They claim that they have to remove transmission and disassemble it in order to find what is damaged.
Does it sound reasonable?

Pascal · 07-23-2012, 08:44 PM

"They claim that they have to remove transmission and disassemble it in order to find what is damaged. Does it sound reasonable?"

Do you really expect a reply when you don't even say what kind of boat, tranny, etc you have??

alexm · 07-23-2012, 08:46 PM

It's a Carver 41 CMY with Volvo Penta D6 - 370 HP

CTdave · 07-23-2012, 11:01 PM

Well the first thing I have seen with shafts/struts/running gear alignment issues is a bad vibration.
You mentioned that they said "they heard some noise". This needs to be explaned better by them. Was it a noise coming from the transmission or was it a noise from rattling/bumping/shaking from everywhere else.
If a transmission in making a noise, it's fairly easy to distinguish over other noises.

Marmot · 07-24-2012, 05:59 AM

Was there any rudder damage? Was the rudder bearing distorted? That can be a source of noise and vibration that appears to come from the drive train.

alexm · 07-24-2012, 06:49 AM

Yes there was a rudder damage, rudder bearing was distorted and then fixed.

dsharp · 07-25-2012, 10:27 PM

If you hit something hard enough to bend the rudders, shafts and struts it very likely tore up the drive plate between the flywheel and the reduction gear. Did you continue to run the boat after you hit the rock or was it towed? I don't know how they could replace the running gear without lining it all up. Why do you think it's an alignment problem?

Gannet · 08-30-2012, 05:35 PM

Sounds like it maybe the motor mounts saw too much shear loading.