whistle noise when shifting in gear

[CapnGary]

Both engines, Velvet drives, a bit of time after changing transmission fluid, developed a whistle like noise when engaged in forward. I repacked the stuffing box, thinking it was that, but it didn't change it. I checked the fluid in transmission. I looked too full, so I took some out and it did not effect the noise.

I have trouble finding out the right level of trans fluid, should motor be running? in or out of gear? does it matter?

It seems to go away when rpms go to 1100 or above, but at idle rpm's and when engaged in gear, both engines have the same noise. Out of gear, no noise.


What could it be?, I'm stumped.

Thanks in advance for any input.
Capn Gary
Milton Fl
1986 32' FB
twin 318's, velvet drives

[javalin390]

Correct fluid? Can't remember if they use Dextron or not. An older post, someone put a link to the PDF file for the Velvet drive service manual. Probably says in there.

[GB49]

Check trans fluid when HOT. Immediately after running the boat at temp, shutdown engines and check fluid level.
Note: Cold fluid level will be OVER the full mark.

I run Valvoline DEX/MERC (for vehicles requiring DEXRON-III / MERCON)
***Don't use fluid higher than DEXRON-III***

[Fastjeff]

Low oil level--which is easy on these since so little oil is used--usually makes a high-pitched whine (like the old Ford power steering pump). Still, you might get lucky and have that be the problem.

As stated above, the fluid level COLD will be at least 1/2 inch or more above Full.

Jeff

[tjcimba]

hi, I have a noise that has similar symptom. It only comes from her starboard engine. I have had a mechanic on board in the bilge while I idled around the waterway. He could not isolate the origin of the sound. I too have thought tranny and packing and strut bearing: all received new fluid or replacement, no luck. Today my thoughts are leaning toward the fuel line and anti siphon/ check valving as possible source?

Any thoughts anyone?

So far PM in the fuel supply area includes changing out the inline filters on fairly regular basis (ceramic perko , water sep and Rochester carb nylon mesh), replaced rubber hose section when I installed the fuel flow sensors, and new fuel pumps each engine several years ago now. The starboard carb was also rebuilt in the same time period as the other work noted here.. The starboard fuel system does have an issue from the fuel tank(?) which manifests itself as a very fine gritty rust colored residue that catches in the ceramic filter but has been observed in the carb filter too.

The noise is like a whine from the starboard 1990 Crusader 305 at idle RPM (3 to 5 knots) when leaving dock within the marina and is annoying and loud enough to be heard by captains on their Sea Rays in their slips as we head out to sea (if you know what I mean). if just a little more fuel and RPM to 6 -7 knots and the noise fades but over speed in the marina here in Milwaukee.

For what its worth, Hope these thoughts help in your effort to solve the whistle noise

Thanks for listening all, sorry to belabor the point but its been an issue for several years now and thought I might find some helpful suggestions since its been mentioned here and having to stay at home.

OFF Topic: When is someone going to start the COVID thread I wonder be safe.

[CapnGary]

thanks for thoughts. I plan on checking the trans fluid stuff again today.

As far as the fuel issues, I haven't done anything to that stuff, but then why would it only 'whistle' when in gear? Out of gear, the noise quits.
Engines start easy and idle nicely, so I assumed the carbs, filters, fuel pump, etc are good and not the problem. But the boat has almost 1900 hours on the meter, and I assume all is original.

Capn Gary

[tjcimba]

Exactly the same with my vessel.

No noise in idle, no noise while under way, engines (around 1200 hrs) start and perform fine and fuel flow sensors show about same usage each engine at various RPM. thinking it may just be a fuel flow issue at the low RPMs, like a wind instrument only whistles at the certain flow???

any advice anyone on replacing hard fuel piping or location/cleaning fuel anti siphon which I have heard we have but not to sure about. Also have exercised all fuel flow petcocks in the system.

Hate that she whines, glad she runs. any thoughts welcomed.

thanks again

[Fastjeff]

..."why would it only 'whistle' when in gear?"

The trans uses more oil when in gear, lowering the level. And since so damn little oil is in these things...

Jeff

[GB49]

Thought about this after my initial post..... (Jeff can back me up on this)....The hose that feeds into the bottom/side of the housing can be removed and you may or may not find an inline screen. Make sure its not dirty/clogged. My trans did not have any screen that I could locate.
Also, depending on available space you may need to modify an open end wrench to fit on the hose collar nut. May want to spray some PB or Liquid Wrench on the area first.

-Karl

[Fastjeff]

You're backed up!

I too made a wrench to get that darn fitting off only to find there was no screen.

Jeff