Velvet Drive problem

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dingy

Member
Joined
Jun 11, 2012
Messages
13
Location
USA
Vessel Name
Invictus
Vessel Make
1977 Puget Trawler
I have a 1977 Puget Trawler, 37' with the standard Ford Lehman 120 with a Velvet Drive transmission. Today I was coming into the dock and shifted to reverse to swing in and nothing happened-the transmission failed to engage. There was no sound like something snapped or no grinding. After docking the first thing I checked was the linkage which was working fine. I shifted into forward and reverse by moving the shift lever by hand and it moved freely but without engaging. The shaft turns freely, meaning there is nothing seized up.
Has anybody run into this sort of thing? What could be the cause?
Thanks for any advice (beside upgrading to a newer model :)
Dingy
 
Ck the fluid level. But you may have bigger problems I had one rebuild the price was not that bad
 
Fluid. We had the same thing happen with our last boat with those drives.
 
velvet drive

Thanks for the reply. The fluid level was OK, so I think it may be a blocked line, or under the heading of "bigger problems". It's a sweet little transmission and has given countless hours of service, now it's time to give back.
Thanks again, dingy
 
We have Velvet drives and experienced a similar symptoms on one side. We discovered it was the drive plate. In separating the transmission from the engine the drive plate was in pieces in the bottom of the bell housing. The transmission was fine.
 
Considering the age of the transmission it is not surprising that it failed. It could be a clogged control valve, worn out o-rings in the reverse clutch piston, clogged oil passage. Obviously the transmission needs to be pulled for an overhaul. After it is cleaned and the clutches, o rings have been replaced, etc, it should be good for another 40 years,

You can pull the neutral safety switch cover off to take a look at the control valve. It might give you an idea of the crud buildup. Clutch plates wear and the material tends to buildup.
 
Not an exoert here, but could be dampner drive plate failure.

From my own experience and research, usually with Lehmans, there is noise and sudden stoppage of the engine as the plate comes apart,.... but it could be that.

You will be able to check the plate as you go to remove the transmission anyway. So there is hope it isnt an expensive or compkicated issue.

Lifespan of dampner pkates on Lehmans starts at about 2500 to 3000 hours. Mine went at 2800 if it was new when the rebuilt engine was installed.

I would replace the plate if it had over 2000 hours on it, only about $175 in parts.
 
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The heart of the VD, and others, is the oil pump; and they are highly reliable. And, its fairly easy to prove that the input shaft is turning, the fluid is intact, and the pump works. It's called a pressure guage, and there is a port for one drilled into the top of the VD, easy to access.
I will say, though, that after dozens of years, the 1/8" (from memory) pipe plug takes a little effort in removing, then you can place a 0 to 300 psi gauge in its place.
 
Easier to check drive plate than a pressure gauge. Start up engine. Take out dipstick and shine a light in the hole. Fluid should be splashing around as guts revolve. No splash, no spin, that means damper plate failure.

If so, when replacing, consider putting in a new oil seal on input shaft. That is the next most likely thing to poop.
 
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checking drive plate and supporting engine

This and other discussions about drive plates make me wonder how you support the engine to remove the transmission. On GB the rear engine mounts connect to the transmission.

Dan
 
Jack or rig up the back of the engine and put wood blocks under the flywheel housing. It is stout enough to hold the weight.
 
drive shaft

when you disconnect the drive shaft, does it affect the alignment or can you just bolt it back in place when done?

Dan
 
I really appreciate all the replys--what a collection of experience. Considering the age, an overhaul would be in order, but it does sound like a drive plate. Thanks for the tip on supporting the engine also, probably something that would be obvious, but nice to know.

Really a great, well managed forum. Thanks again,
Dingy
 
The local place that I took my transmission to said a rebuild will cost more than a "rebuild" by one of the top places that do it.

They recommended if the tranny was working fine, they drain, check the screens, replace front and rear seals and refill. Run till you need a rebuild.

Because I took it out myself and to the marina service department, it was a little less than $500 with some shaft polishing.

If I had to pay someone to do the removal and install...then the $3000 grand or so for a rebuilt tranny at that point may be more cost effective.
 
The issue could also be rust in the reverse cylinder. Mine had it and I caught it while it still functioned. I was able to clean it up easily during my rebuild.

A friend's had much more corrosion and it would not go into reverse. Then it self destructed.

If water ever gets into the tranny it goes to the reverse cylinder and can't get out unless you turn the tranny upside down and drain it. At least that was what I was told by a 70 year old boat mechanic who worked on Velvet Drives most of his life.
 
when you disconnect the drive shaft, does it affect the alignment or can you just bolt it back in place when done?
Dan

You should always check the alignment. You may get lucky and no adjustment is needed.
 
If it's the transmission, the people to talk to are Harbor Marine in Everett. They have rebuilt VD's on the shelf or will repair yours. They're very knowledgeable and nice people to work with:

Harbor Marine
1032 W Marine View Dr, Everett, WA 98201
425-259-3285

https://www.harbormarine.net/services
 
Because I took it out myself and to the marina service department, it was a little less than $500 with some shaft polishing.

Wow P that is a great price. I took mine to a local (car) transmission shop and they charged $700.00. All new cluches and I don't remember what else. I did the R&R.

The local marine shops started at $1,200.00 if I brought it in.

Rob
 
Just an update on that Velvet Drive problem. We removed the transmission and it was the drive plate. There is a smaller center plate with the grooves that go over the transmission spline which is riveted on the large plate having the springs. all the rivets were sheared off. Except for the rivets, everything else looked in good shape.
Long story short, the transmission was brought to a shop and everything checked out. With the new plate and the service at the shop the bill was under $500. Put things back together (being very careful not to force the last 1/4" by sucking it in with the bolts) and everything works great. Thanks for all the help, you guys were spot on on the diagnosis.
 
velvet drive

Interesting thread...If a pressure gauge is installed, what is acceptable pressure for a transmission that is operating properly?
What does HP mean?
What dfoes low pressure mean?

Bob
 
Service manual gives detailed specs.
Ex: at 600 rpm in neutral - 117-130 psi.
 

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