Twin Disc trany

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Steve1.0

Senior Member
Joined
Aug 6, 2020
Messages
229
Location
U.S.A
Vessel Name
Kumatage
Vessel Make
Grnd Bnks 46 cl
My stb. transmission seems to be slow to go into reverse.(2seconds +-). Oil level is good, they go into fwd quickly. Is this normal. Someone told me that mfg. allows up to three seconds for reverse to engage. True?
 
What is the model and actuation mechanism? Manual controls or are they being operated by fly by wire?
 
My stb. transmission seems to be slow to go into reverse.(2seconds +-). Oil level is good, they go into fwd quickly. Is this normal. Someone told me that mfg. allows up to three seconds for reverse to engage. True?

Hi,

i also have a twin D and usually it works immediately when i put the lever in the free position forward or backward.

The exception is if the oil is cold at about 0-6C then the switch will take several seconds to hit. as an oil SAE 30 oil, according to the plate, ATF oil could also be used in the gear unit.

Have you looked at the plate on your clutch and oil quality and level the surface check when the oil has warmed up to the normal level.

NBs
 
Twin Disc MG5061A 2.47/1 Shifting seems to take a smidge longer when warm. ??
 
Last edited:
Twin Disc MG5061A 2.47/1 Shifting seems to take a smidge longer when warm. ??

Hi,

see user guide and troubleshooting (link).

Check your clutch pressure, temperature and oil level as instructed, also check the correct oil viscosity and quality.

You will find all the link in the guide and some information about your clutch, with the plate where the information about your clutch model, pressure, heat and the correct oil.

https://twindisc.com/wp-content/uploads/2021/03/MG-MGX-Operators-manual-1016313_RevL_0818_CD.pdf

NBs
 
Shifting speed also depends on the idle speed. Pressures drop at low RPM and this will delay shifts since it takes more time to pressurize the actuator. Velvet drives are exactly the same. I would not consider 2 seconds to be concerning. Mine have some delay at 600RPM as well. Do you have drive pressure gauges? I know mine do and the pressure is lower at low RPM.

As a side comment I had a professional captain aboard to do some maneuvering into a lift. He said he preferred to keep the RPM up at 800+ because of shift delay at low RPM. I don't simply because I don't like 'banging' the drivetrain but I know that there is a delay between moving the lever and actual engagement.
 
As a side comment I had a professional captain aboard to do some maneuvering into a lift. He said he preferred to keep the RPM up at 800+ because of shift delay at low RPM. I don't simply because I don't like 'banging' the drivetrain but I know that there is a delay between moving the lever and actual engagement.


I think thats what I may be experiencing. I'm going to give the rpm a bit more and see what happens. If it shifts faster I'll know what I'm dealing with.
Thanks for the replys.
 
Shifting speed also depends on the idle speed. Pressures drop at low RPM and this will delay shifts since it takes more time to pressurize the actuator. Velvet drives are exactly the same. I would not consider 2 seconds to be concerning. Mine have some delay at 600RPM as well. Do you have drive pressure gauges? I know mine do and the pressure is lower at low RPM.

As a side comment I had a professional captain aboard to do some maneuvering into a lift. He said he preferred to keep the RPM up at 800+ because of shift delay at low RPM. I don't simply because I don't like 'banging' the drivetrain but I know that there is a delay between moving the lever and actual engagement.

I don’t mind slamming your engines in gear either…. But on my boat I don’t want to do that. I like low RPM shifts unless it is an emergency.
 

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