Volvo Penta DPH-D stern drive issue / upper gear

[Digi78]

Hey,

I have two Penta D6-400 engines with DPH-D1 sterndrives and last summer I noticed certain vibrations coming from sterndrives or engines (difficult to say the exact place when you are driving 27knots). Now I asked my service partner to check the potential reason for vibration/sound and they found out that the upper gear of the stern drive needs to be replaced (it is worn out or the “coating” has damaged”). It is just the another drive.

Is this normal as there is only 650 hours with these engines / drives and all the services done on time in official Penta service partner. The cost of replacing the upper gears is around $6k (per stern drive).

And the worst part is that they confirmed that the sound or vibration is not coming from this issue and they need to detach the engine to find out the reason….

 

[spannerman]

The only time I have seen the hardening on the gears damaged is through low oil level, or water in the oil but then it is usually the lower gears that fail as the water tends to settle at the bottom of the drive. There is a procedure to filling these drives, they should be trimmed up to about 35 degrees and filled until the oil is at the bottom of the filler hole, then the plug fitted and the drive trimmed down and up a couple of times then returned to the 35 degree angle and you can then get more oil in as you have removed the air pocket, the drive should hold 5.4 litres if you have less then the upper gears risk running in air not oil.
If the hardening is worn I would also check the pinion in the lower section as its the smallest gear but has to transmit all the horsepower to the other gears, these usually fail first if driven for a while with water in the oil. I always check this gear if the oil is contaminated as you have to remove the hub anyway to fit new seals.
I have not experienced vibration from the symptons you describe, vibration is usually from a worn universal joint. I would check that and also for play on the intermediate shaft in the transom and for correct preload on the input bearing on the drive.

 

[Digi78]

The only time I have seen the hardening on the gears damaged is through low oil level, or water in the oil but then it is usually the lower gears that fail as the water tends to settle at the bottom of the drive. There is a procedure to filling these drives, they should be trimmed up to about 35 degrees and filled until the oil is at the bottom of the filler hole, then the plug fitted and the drive trimmed down and up a couple of times then returned to the 35 degree angle and you can then get more oil in as you have removed the air pocket, the drive should hold 5.4 litres if you have less then the upper gears risk running in air not oil.
If the hardening is worn I would also check the pinion in the lower section as its the smallest gear but has to transmit all the horsepower to the other gears, these usually fail first if driven for a while with water in the oil. I always check this gear if the oil is contaminated as you have to remove the hub anyway to fit new seals.
I have not experienced vibration from the symptons you describe, vibration is usually from a worn universal joint. I would check that and also for play on the intermediate shaft in the transom and for correct preload on the input bearing on the drive.

Thank you for the detailed response and insight you shared - much appreciated!

It seems that the stern drive service (even oil change) is something special that all the service partners are not able to do properly.

 

[spannerman]

Yes over the years I have seen some bad practice by engineers who think they know better than the manufacturer, I always follow the procedures as written in the workshop manuals by the people who designed and built the machinery.