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Old 01-21-2022, 08:04 PM   #1
Veteran Member
City: Ladysmith
Vessel Name: Dauntless
Vessel Model: Grand Banks 36 Classic #248
Join Date: Sep 2019
Posts: 43
BW Velvet Drive Transmission


Ive been giving my engines a major service, started off removing the exhaust elbows to clean them out, ended up having to replace them. Ive now moved onto the engine and transmission oil coolers, as I don't have any history of the boat (estate sale) I decided to change all the hoses and coolers. While removing one of the transmission coolers the end cap fell off so I'm quite pleased with my decision.

The boat is equipped with two Ford Lehman 120's with BW Velvet Drive transmissions Model AS7-71C, both transmissions are the same but one appears to have been modified. From the manual the oil take off to the cooler is in the top, center of the transmission housing, the return is supposed to go to a plug on the bottom right side of the transmission housing.

On one transmission the hoses are rigged up as they should be but for some reason the return oil line on the other goes to hole cut and tapped into the top of the reduction gear housing, this completely bypasses the gearbox screen filter. I would like to know if anyone else has seen this modification and if so why it was made.

I would also like to know if there is an off the shelf rattle can that matches the Ford green on these engines.
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Old 01-21-2022, 08:52 PM   #2
City: Boston
Vessel Name: Adelante
Vessel Model: IG 30
Join Date: Nov 2016
Posts: 1,445
Good call on replacing the oil coolers.

I don't see any advantage to rerouting the return line to the reduction gear. The PO must have had a reason but I can't think of one other than it might have been noisy.
I would reroute the return line back to where it belongs and plug the hole on the reduction gear. Easy to change back if you rediscover the original reason.
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Old 01-24-2022, 07:45 PM   #3
Veteran Member
City: Ladysmith
Vessel Name: Dauntless
Vessel Model: Grand Banks 36 Classic #248
Join Date: Sep 2019
Posts: 43
Found the Answer

After quite a bit of research I think I have found the answer. It appears there were four versions of this transmission, on the first edition the return oil was fed to a lower connection at the bottom of the bell housing, on the second and third versions it was fed to the lower connection on the Fwd/Aft housing (as in the photo above) and on the fourth version the return is on the top of the bell housing (again as in the photo above). I think at some stage one of my transmissions was replaced by a previous owner.
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Old 01-24-2022, 10:29 PM   #4
City: Montgomery
Vessel Name: Choices
Vessel Model: 36 Grand Banks Europa
Join Date: Apr 2018
Posts: 576
Call Mike Voght at Harbor Marine. He can answer all those questions. He just rebuilt mine.
36 Grand Banks Europa
Montgomery, TX
Blog: "grandbankschoices"
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Old 01-25-2022, 11:51 AM   #5
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City: Gulf Islands, BC Canada
Vessel Name: Soo Valley
Vessel Model: Grand Banks 36
Join Date: Jul 2019
Posts: 2,885
Not at the boat now, but I recall my twins have oil hoses in different locations. I have accepted that because one tranny has a reverse gear so the two props do not turn the same way. That addition may require the different route for oil to/from cooler.
SteveK AKA Soo Valley
You only need one working engine. That is why I have two.
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