Velvet drive skipping under heavy load?

[biggsie]

Finally got out to set up surf wave with some friends and more ballast. Waves were starting to look great with 750 in rear corner 400 next to motor cover and another 400 up front. Just when I thought "sweet let's try it" the boat skipped and shuttered and I could feel the boat slow like the prop stopped spinning for a split second. Wtf was that!!!

Note: originally the fluid was milky so I replaced the cooler and flushed twice. Boat has had about 4 hrs of runtime since with no milk.

When checking fluid after the issue the cap kinda popped off like there was some pressure buildup. Shouldn't it be vented?

Added some ATF and emptied ballast and it was fine. Tried surfing again and the same thing happened.

I'm obviously thinking I need new clutches or something but the drive seems great without ballast even on WOT pulls.

Any help here ??


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[csuggs]

Could be the damper plate.


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[Cusefan78]

My bet is the drum is cracked. Pretty common problem. Had to change mine when I changed out my clutch discs

[lively]

My bet is the drum is cracked. Pretty common problem. Had to change mine when I changed out my clutch discs

Please tell me how a cracked splined drum would cause the velvet to slip in forward gear ? How many of these drives have you personally rebuilt ? It is not common for the drum to crack , now if you run it low on fluid and don't add then yes the pressure would build and things would give way .

In his case the fluid is hot and his friction disc are worn , thus causing slipping in forward gear . 4 hours with a rebuild kit and should have no issues


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[biggsie]

I have removed the pop-off vent and replaced it with a vent hose. Flushed fluid one more time and will try it again. Really hoping I don't have to pull tranny in the middle if summer.


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[Cusefan78]

Mine was slipping it did have worn discs. Talked to Vince at skidim and he told me drum cracks are common and will prematurely wear the discs. Sorry for giving my opinion I'll just but out, clearly you are the transmission man here. Oh and just a heads up a cracked drum will cause pressure loss which will make the discs slip. But once again I'm clearly an idiot and you are the man.

[biggsie]

Just out of curiosity, what does a "slip" feel like to you guys? All the clutches I've ever felt slip feel like the power isn't coming in strong enough and it's a smooth low power feeling.

This feels like a jerk into neutral to me.


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[Cusefan78]

Mine felt like cavitation when i tried to get out of the hole or turned hard. You'll know if it's slipping

[biggsie]

I guess that's what I was feeling then.

Think I can get through the season without it getting worse if I just don't surf?


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[Cusefan78]

I tried that, got 1/2 of another weekend. I think once they start to slip they degrade quickly.