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September 23, 2017, 09:13:02 AM

Author Topic: Direct drive transmission squeal  (Read 250 times)

Sammamish Skier

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Direct drive transmission squeal
« on: July 07, 2017, 23:32:55 PM »
While out skiing today we noticed a strange squeal from what appears to be our transmission when the shaft is barely turning and the boat is in neutral and coming to rest. I think these transmissions have a brake so maybe it's worn? Fluids look normal, but I'm going to pull the filter to check for debris. The transmission sounds fine otherwise. Anyone ever run into this?

Capt Rick

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Re: Direct drive transmission squeal
« Reply #1 on: July 09, 2017, 00:41:15 AM »
The direct drive when in nuetral should not turn the shaft. ( indicates bad clutch plates)

The gears should be quite above 1200rpm. in gear, rattle is common under 1200. ]


Bad shaft packing, bad alignment, worn cutlass bearing are all items that can squel.

Capt Rick

Sammamish Skier

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Re: Direct drive transmission squeal
« Reply #2 on: July 09, 2017, 15:05:24 PM »
I dont think it's the clutch as the noise comes from the output shaft coming to rest when the prop is driven by the momentum of the boat.  I'll have to check the packing and alignment.

Water Sports

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Re: Direct drive transmission squeal
« Reply #3 on: August 03, 2017, 22:37:16 PM »
We had same noise at low idle.  Found out to be thrust plate between flywheel and trans.  Caused by corrosion of bushings on plate.  Only way to find out is to remove trans.  Didn't cause any damage just annoying. Doug

Sammamish Skier

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Re: Direct drive transmission squeal
« Reply #4 on: August 04, 2017, 15:46:33 PM »
Took the boat to a shop it appears that this was an air leak in the filter seal. Still testing to be sure. On a positive note the hsw450 which is in the direct drive boats is still being made as the  zf45a and according to ZF it can get conditional approval from the factory for use in our boats given that WOT is 500 rpm above factory specs for the zf45a.

Sammamish Skier

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Re: Direct drive transmission squeal
« Reply #5 on: August 22, 2017, 02:01:44 AM »
One more update on this. The squeal returned shortly after I made this post. Had the alignment checked and it was fairly far out. Fixing the alignment got rid of the squeal. It also made the boat quieter at speed.