BW Tranny Problem

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Dixie Life

Senior Member
Joined
Feb 4, 2011
Messages
213
Location
USA
Vessel Name
Aku Uka
Vessel Make
43’ DeFever
My tranny makes a loud clunk when I go to reverse, only reverse.* When I go to foward, smooth and quite.* I'm sure it is a linkage adjustment problem.* Can anyone advise me on how to adjust it.* It's a Borge Warner Velvet Drive on a FL120.

Thanks
 
The Velvet Drive has only one drive plate for reverse, vs several for forward. Thus the transmission is weaker in reverse than in forward. If you have a Velvet Drive manual the shifter settings are in it. However I have heard of this clunk on the Grand Banks owners forum several times, and I recall the cause had nothing to do with any adjustment of the shift mechanism. It was due to a part wearing out or breaking but I don't recall exactly which one.* A misadjusted shift mechanism will cause the transmission to slip and overheat as well as wearing out the clutch or drive plates. The clunk is something else, as I recall. Possibly one or more broken springs in a clutch plate or drive plate, which ever one has the springs in it.


-- Edited by Marin on Monday 14th of November 2011 06:57:21 PM
 
Marin wrote:
Possibly one or more broken springs in a clutch plate or drive plate, which ever one has the springs in it.



-- Edited by Marin on Monday 14th of November 2011 06:57:21 PM
*You are probably thinking of the damper plate which is not part of the transmission. It is the part that is bolted to the engine flywheel that powers the tranny input shaft. It is a wear item and costs "about" $100-150 . I bought a replacement from ADC a few years ago when I rebuilt my BW tranny.

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I have a Paragon box on my L120, and it works well, and has given extremely faithful service, but one thing I found was if the fluid gets low it makes a strange swooshing sound at power on, and also that if you don't screw the filler plug fully in after refilling, (just the thing one is tempted to do just to run the engine then check the level again, because it is quite long and tedious to screw right in, being quite a long bolt-like arrangement), the reverse does not work at all. So obviously it performs two functions - filler hole and the shaft closes off some kind of oil gallery. Anyone else have this type of tranny, or are they all Borg Warner Velvets over there...? I've never heard anyone on the forum mention a Paragon transmission.
 
Paragons are a very robust transmission.* I had several on older sail boats.* They were mated to Atomic fours as well as Yanmars and*a lot of other engines.* Most of the engines they are mated to do not produce the HP that they are really rated for so they last a long time if kept in adjustment. I was told that they were designed and*used for industrial engines in the 400 HP range so boat engines under 300 HP were child's play for them.

They have a clutch pack that is wet, a sun gear and an outer brake band somewhat*like an old Powerglide Chevy transmission. The clutch pack is engaged by the lever which forces the clutch to clamp down on the clutch pack which consists of 6 or 8 plates*which are separated by steel plates,*the steel plates*are keyed to the main input*shaft from the engine.* This causes the sun gear housing to rotate and deliver power to the prop shaft in the same direction as the engine is turning.* Reverse is accomplished by the lever being moved in the other direction which also releases the clutch but at the same time engages a brake band around the outside of the sun gear housing. By holding the outside of the housing the inside is forced to turn in the opposite direction and thus you have reverse.

The critical adjustments are done on the brake band and on the clutch throw.* Both are done with the top off of the transmission.

I understand parts are becoming a problem here in the US.* When I rebuilt the on on my sail boat seven years ago there was a place in Ft. Lauderdale that had every thing I needed.* One bearing was the most expensive part.* It was a special size and it was over $200 US.* No one had a match including Timken.
 
Ok, well thanks for that info JD. I better hope she just keeps on keeping on then, and I take heart from your comment...
"I was told that they were designed and used for industrial engines in the 400 HP range so boat engines under 300 HP were child's play for them."

Thanks.
 
I asked my mechanic at North Harbor about Paragons and he says like the BW Velvet Drives they are very robust and rock solid. *Change the fluid by the manufactures recommendations and keep the sea water out of them and you should have no problem. *Most of the trannys he sees failing are from lack of service or the oil cooler fails and floods them with salt water. *He was curious about your lost fluid though, are you losing a seal? *Props and shafts out of balance or misaligned shafts may damage the rear seal and cause fluid leaks.

He remembered working on two early 70's 31' Uniflights with Nissan 6 cyl diesels and Paragon V-drives. *He says they only made the two prototypes and discontinued them. *They had a problem with repeatedly blowing the oil seal on the output shaft side of the drive. *But he says that those V drives were probably an adaptation of a unit meant for gas engines.*

Larry B


-- Edited by Edelweiss on Friday 18th of November 2011 09:04:14 AM
 
Edelweiss wrote:He remembered working on two early 70's 31' Uniflights with Nissan 6 cyl diesels and Paragon V-drives. *He says they only made the two prototypes and discontinued them. *They had a problem with repeatedly blowing the oil seal on the output shaft side of the drive. *But he says that those V drives were probably an adaptation of a unit meant for gas engines.*
Larry B
*The V drive on my*38' C&C was a Walters V-Drive 2:1*bolted to the Paragon Gear box.* That was several (8)*years ago but I seem to remember that the folks in Ft. Lauderdale told me that Paragon didn't make a V-drive.* The V's*were always a bolt on.* I could be wrong. About*Paragon making a V-Drive but*not the fact that mine was a Walters.

The Paragon used ATF and the Walters used*Hypoid<a></a> 90

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Paragon V Drive example (below)*

But I think you got it backwards though, sounds more like Walters makes V drives and not gear boxes. This is*the Walters V Drive fact sheet info.

WALTER V-DRIVE

Direct mount means that the v-drive is directly mounted to the transmission, usually a Borg Warner Velvet Drive, that*provides the forward - neutral - reverse function. The driving transmission is always 1:1 ratio and any*gear reduction is done in the v-drive.

1. All Walter V-Drive units use 30 W non-detergent motor oil.

2. Alignment of the output flange to the prop shaft flange is required to be within 0.003 inch.


-- Edited by Edelweiss on Saturday 19th of November 2011 12:20:37 AM
 

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