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Scot 01-31-2013 12:19 AM

Transmission Slipping?
Finally time to tackle an issue I was having last season. Some of you may have seen my stringer thread last year. I bought the boat one year ago, tore it down and got it done by summer only to get to use it a handful of times due to some family circumstances. The times I did have it on the water I was working out bugs and got all but one figured out.

On hard takeoffs as well as hard turns the transmission seems to be slipping. The engine runs great, no hesitation, just revs without full engagement. Prop is tight, key is intact. A friend of mine that owns a local boat shop claims that these transmissions "don't really slip, " which I find hard to believe.

I do know that it leaks fluid and have yet to track/fix that. The issue persists even though I have topped off any lost fluid each time.

I know my boat pretty well inside and out, except for whats inside that little box between the motor and shaft. Pretty sure I could handle a rebuild so long as it doesnt require any crazy specialized tools. Anybody have any insight as to the cause?


Scot 01-31-2013 12:24 AM

Forgot to mention, its a powerslot.

willyt 01-31-2013 10:46 AM

it can definitely slip if the tranny fluid is low, but it sounds like, if it only does it in hard turns, that you're experiencing cavitation.

what kind of boat do you have? some are more prone to it than others, i only experienced it once on my 05 X2, but my 07 star seems to love to cavitate. I've heard the 5 blade doesnt allow as much cavitation.

TRBenj 01-31-2013 11:36 AM

The can also slip if the clutch plates are worn. Low fluid in a tranny on its way out can cause slipping or even pop out of gear- but thats not the only thing that will cause it. Combined with the leak youre seeing, I'd say its rebuild time.

PureInboards 01-31-2013 02:41 PM

Last thing you want to do is re-build for no reason but best thing to do is pull the dipstick and smell the oil, if smells like its burn't there is a pretty good chance the clutch packs are slipping but defiantly check out possible cavitation first and even try another known good prop just in case the prop has been repaired/modified during its life

Kyle 01-31-2013 05:24 PM is where I got my rebuild kit from. I think it is the cheapest place to get a master rebuild kit.

When I did mine I assembled everything and had the same problem. My clutches were worn and needed replacing but my front pump was bad. So I had to remove the tranny and put a pump in. It worked very well after that.

Scot 02-08-2013 12:38 AM

Any advice on whether it is worth swapping from a powerslot to a 1:1 velvet drive? Longer shaft needed?

I have owned and driven many ski boats in my day and have never had an issue with a 1:1 lacking low end power. The powerslot seems unnecessarily low geared. Top speed is just about 40 MPH and I would rather have a little more top end and better fuel economy. Maybe my problem is due to wear? Can I get the same top end performance with a fresh tranny and a different prop? Not looking to race or anything, just want a little better fuel economy at 36+ and more at WOT than 40-.

Scot 02-08-2013 12:42 AM

BTW, definitely not cavitation. It does this out of the hole, when everything is in the water. When I say hard turns I mean moderately hard turns. I know how to make these things cavitate if I want to, its definitely not happening. Gotta be the tranny.

[email protected] 02-08-2013 10:38 AM

Reason for slipping either low pressure or worn clutch plates low pressure can be caused by low fluid or leak I and a leak in my coolent line internally then leaked out the casing of the hose in a hard to place once the tranny starts slipping you are wearing the clutch plates excessively if it were me I would find the leak and rebuild

Scot 02-12-2013 12:47 AM

Is pump replacement considered a typical part of a rebuild?

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