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Old 01-26-2021, 11:25 AM   #1
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Velvet drive issues

My Velvet drive goes into gear just fine but after a half an hour or so of running the shaft speed slows way down and eventually will stop even though the engine RPMs have not changed however it seems to work just fine in reverse
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Old 01-26-2021, 11:50 AM   #2
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Is the oil level is good or not good, in either case the oil should be changed and look at the used oil, send a sample to a place like Blackstone for analysis. Look for water in the oil. That would suggest a heat exchanger in need of replacement.
If new oil does not help, you will most likely need to rebuild it as it then sounds like slippage. Just a wag.

Oh, and welcome to the forum
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Old 01-26-2021, 12:41 PM   #3
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they will do this if the linkage is out of adjustment. make sure the transmission is all the way in gear.
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Old 01-26-2021, 02:24 PM   #4
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Sounds like forward clutch plates are slipping once it gets to operating temp.
As mentioned, make sure linkage is full forward, oil is full.
Replacing clutch plates is a rebuild. Transmission must be removed, disassembled, and then rebuilt. Doable for any experienced mechanic. If you deliver to a shop you might get lucky with $750-$1250 overhaul. Price goes up if they find pitted shafts, bearings, etc.
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Old 01-27-2021, 08:44 AM   #5
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Hiya SoWhat, "Sounds like forward clutch plates are slipping once it gets to operating temp"...is this a normal wear issue, and, are there reverse clutch plates?
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Old 01-27-2021, 08:57 AM   #6
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Originally Posted by artfulltune View Post
Hiya SoWhat, "Sounds like forward clutch plates are slipping once it gets to operating temp"...is this a normal wear issue, and, are there reverse clutch plates?
There are separate forward and reverse clutch plates. Is it a normal wear issue? Not really, given good oil of the proper level they last a very long time, easily 5000 hrs in trawler use. Low oil, oil contaminated with water, incorrectly adjusted shift lever can all cause the clutches to slip and once they start slipping clutch wear happens very quickly.

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Old 01-27-2021, 09:40 AM   #7
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Do check that fwd takes lever on gear to where the detent ball clicks in.

Seen some with the wrong dipsticks, causing oil level to be low. Add half a qt of fluid and see if problem goes away.
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Old 01-27-2021, 11:06 AM   #8
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Unlikely this is the complete cause but make sure the ATF oil cooler in & out ports are pointing up in your installation. If pointing down, fluid runs out of the cooler into the transmission when you shut down giving a false high reading when stopped to check and a lower reading when running.
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Old 01-27-2021, 12:58 PM   #9
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Hiya kchace, had no idea of a reverse plate in my drives...i.e., knowledge is power.
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Old 01-27-2021, 01:06 PM   #10
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Originally Posted by Johny12b View Post
My Velvet drive goes into gear just fine but after a half an hour or so of running the shaft speed slows way down and eventually will stop even though the engine RPMs have not changed however it seems to work just fine in reverse
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Old 01-27-2021, 01:19 PM   #11
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Hi Johny, hope you will stick with us and also let us know how you resolve your issue - the solution is doubtless in the preceding posts!
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