What transmission is this

[EC Sailor]

Fellow crusiers I need help identifying the transmission on my boat.

It is a 73 allied mistress with a standard perkins 4-108 diesel and a tranny that I can't id. The boat doesn't have a prop lock so the prop is always free wheeling and the tranny gets quite hot if I do not run the engine every 5 hours or so to keep the transmission fluid cycling for cooling purposes.

[lookoutnw]

Sounds like a velvet drive to me. I got one also. Good tranny. I use amzoil tranny fluid. It keeps it cooler and is better for it. Also, a prop lock is wasy to make from a piece of wood and a flat rubber band. Look at a strap wrench and modify the concept. My handle has a 1 1/4 hole in it, then I cut 1/2 teh hole off. I attached the rubber band on the bottom, run it around the shaft 2 times and jam cleat to the top. It doesn't take much to stop my 19" 3 blade prop but if I start going with the Perkins 4-236, it will spin the prop. It will burn teh rubber and not mar the shaft... KISS

[James S]

My Velvet Drive has no problem free wheeling...doesn't get hot.
Its a model 72.

[Steve Pope]

Borg warner boxes don't do freewheeling, they rely on the oil pump for lubrication and that only works when the engine is running.

[lookoutnw]

THat is why you are supposed to start them peiodically, some say every 8 hours, to cool them down. Probably depends on how fast the shaft turns when sailing. Mine start slight hum at 4.7 knots and sings at 9+.

[James S]

From “Velvet-Drive”:
It has been determined by tests and practical experience that all Velvet Drive marine transmissions call be free-wheeled without risking damage in sailing or trolling applications. Caution should be taken to be sure that proper oil level is maintained prior to freewheeling as well as normal running. Freewheeling one propeller of a twin engine boat at trolling speeds will not cause damage to the transmission connected to the freewheeling propeller.
Extended periods of free-wheeling at high speeds may cause the transmission to overheat; therefore, it is recommended that transmission sump temperature be monitored and free-wheeling discontinued whenever 230 degrees F or 111 degrees C is reached.

[SkiprJohn]

Send a photo of the transmission and maybe we can id it. Velvet drives can be free wheeled but many other transmissions can't and some have to be placed in reverse. There is no reason to speculate about what transmission it is someone here can identify it by photo. I know what old Velvet drives look like but can't tell what some of the newer or different transmissions are.
kind regards,

[EC Sailor]

SkprJohn
Here are a few pics of the transmission. It had two cooling lines that are attached to the oil cooler on the Perkins 4-108.

[lookoutnw]

Yep, Velvet drive.

[lookoutnw]

A lot if not all 4-107/8 & 4-236 have them.

[EC Sailor]

So now that I know what I have, what is the best course of action.

I figure I can either stop the freewheeling prop our get a feathering prop. Thoughts gents.

Lookoutnw what type of amsoil are you using, how much are you using power change and how often are your changing it.

[lookoutnw]

I don't figure on changing it since I have a SAILBOAT... OK, My fingers are crossed.
Marine Tranny fluid.
Did you see my thread about the prop stop handle/wrench/gadget/whachamacallit/thingy?
Stops mine easily.

[lookoutnw]

NOte: I have the ignition key on it so I remember to get it off before I start the engine. Also, it just rests against the underside of my shower floor. There is really very little pressure required to stop them. I can do it by my hand up to about 6 1/2 knots.

[EC Sailor]

I saw it, I was thinking of using a channel lock plier but I do not want to mar the shaft.

Am replacing the oil in it with amsoil tramny fluid. Any other recommendations for taking care of the velvet drive tranny are very much appreciated.

[Unicorn Dreams]

I use a long 3/4" box end wrench that fits the shaft coupling to the transmission, with said keys attached. Does make a heavy key chain.