Servicing Twin Disc MG-502

[Alaskan Sea-Duction]

So I am changing the oil in my transmissions. My service manual says this service consist of draining the oil, cleaning a screen, then putting in new oil (all 3.5 pints). Then you start the engine and check the oil level.

My manual says to use either 30w or 40w oil. Not transmission fluid?

 

[BerettaRacer]

Sounds right, my ZF's are standard L.O. and so are many others I've serviced over the years

 

[Chrisjs]

Must use plain vanilla 30W or 40W (probably best 30W in your region), No multiweight!! No detergents!! Can be hard to find these days.

 

[Crusty Chief]

Tom,
A fellow Selene owner recently has a transmission failure due to a maintenance tech that used wrong weight oil. Better check with manufacture for their recommendation.
As I recall, the tech used 40w and should have used 30w. I find it hard to believe that caused the failure, but 30K to replace is enough to make me think twice.

 

[Chrisjs]

I used 30W in my MG5050 on a Selene 47. 40W is recommended for warmer climates.
Both are specified by TW. Just make sure it is plain old 30W or 40W dyno oil, not synthetic, no detergents, no multigrade.

 

[Alaskan Sea-Duction]

Tom,
A fellow Selene owner recently has a transmission failure due to a maintenance tech that used wrong weight oil. Better check with manufacture for their recommendation.
As I recall, the tech used 40w and should have used 30w. I find it hard to believe that caused the failure, but 30K to replace is enough to make me think twice.

Depending on operating conditions, 30w or 40w per manufacture's service manual (See Pic). Good call on non-detergent oil.

 

[Chrisjs]

While we're on this topic, you are supposed to read the TD dip stick while engine is running at idle. Th is tricky because the oil tends to move around and does not give a clear level reading, especially hard to see with fresh clean oil. Easier to check/correct level before draining, then refill with exactly same volume of clean oil.

 

[Bustlebomb]

You made me think of a question... I know the manual says to check the dipstick with engine at idle but, if I fill it to the proper level and then check the dipstick with the engine off (yes, I realize it will be at a different level than the "full" mark), would that be a valid measuring point as well? Wouldn't I be able to tell if it's low based on the cold level? In other words, if the oil level was correct and the level didn't change, would that be a sufficient indicator that all is as it should be?

 

[hmason]

I have those trannies. Where is the screen? And my CAT mechanic said that you can note the "engine not running level" and use that for future measurements. I don't know if he's right but I use the engine running method.

 

[Alaskan Sea-Duction]

I have those trannies. Where is the screen?

My finger is pointing at the screen. It is a bolt, O-ring and screen.

The manufacture is stating to check it while running. My truck tranny is the same way.

 

[hmason]

Got it. Thanks.

 

[Portage_Bay]

I cared for and ran a Twin Disc MG 530 for decades and over 20,000 hrs. The above posters are correct. Non-detergent, non-syenthetic only. Yes, the wrong oils will ruin these transmissions. Detergent oils will froth and the moving parts won't be properly lubricated. Synthetic oils are the wrong oil for the metals.

And do check the level at neutral idle. After an oil change I will also check again at days's end just before shut down. The hot level is different than the cold level.

When cleaning the screen avoid the use of "blue shop towels". They leave particles that can cause problems.

Treat a Twin Disc MG transmission right and it will never let you down.

 

[C lectric]

Your manual in the first photo, section #1, Oil Service Class, says NOTHING about a non detergent oil. In fact it calls for CD which a standard , although now old spec., engine oil which was detergent.

Simply get a good quality 30w engine oil and it will be fine. 40W if the gear runs on the warmer side.

I use 30W engine oil in my 506.

As far as level checking I do check while running so the filter, if any, the lines and the cooler are all full. Once I know that the level is good running, then the next day, after allowing the typical drain down, I will then check again. The level will be up so I make a note of where and then I can check when not running. Should still be done running but it means that if the engine is not running and you want to check you can then get a least a reasonable check.

http://www.apicj-4.org/2009_engine_oil_guide.pdf

You will find the CD and CC designations near the bottom. But they were detergent oils.

 

[Alaskan Sea-Duction]

Thanks C lectic, interesting.....

 

[Pgitug]

Must use plain vanilla 30W or 40W (probably best 30W in your region), No multiweight!! No detergents!! Can be hard to find these days.

NAPA auto parts always has non-detergent oil.

 

[Alaskan Sea-Duction]

When you are wrong you are really wrong!

Sometimes getting old sucks. I am down in the ER looking at the trannys. I look at the ID plate and it say MG 507-1. I am looking for the screen filter and can not locate it What the heck my book says there is one right next to the oil pump. I also notice I don't have a breather cap, I have a fill cap. mmmmm

I am still not getting it.

Then I pass the lower helm, look at the manual that came with our boat.

Well crap!

I don't have MG-502. I have MG 507-1 WTF????

So now I need to find the proper manual for my trannys....

Any ideas?

 

[RT Firefly]

 

[Alaskan Sea-Duction]

Thanks RT.........

 

[C lectric]

I have the 506 model so not directly related but close.

The fill cap is also the breather. Remove it and flip upside down and I think you will find it is filled with fibres to stop oil splash and dirt entry but also allow air in and out. Take a look inside the fill tube and I think you will see a lip. When filling be carefull as the oil will back up the fill pipe causing an overflow, mess, as the oil is slow to pass that lip.

http://www.marind.ca/medias/pdf/produits_marins/twindisc/td_operators_manual.pdf


Link is a T.D. generic manual but some of the info you want is in it. Suction screen in section 6-2.

Oil is there also.

E bay has some manuals for the 507-1 available. If not now then keep checking.

manual: Twin Disc 507 | eBay

I noticed that the T.D. manuals were CAT manuals so maybe try a Cat dealer. A lot of T.D. gears were fitted behind 3208 so they appear to have printed their own version.

 

[C lectric]

ASD.

Read the post from Tony Athens in the following:

http://www.trawlerforum.com/forums/s6/twin-disc-shifting-issue-28791-2.html#post494055

Take if from him about your choice of oil.

 

[Alaskan Sea-Duction]

ASD.

Read the post from Tony Athens in the following:

http://www.trawlerforum.com/forums/s6/twin-disc-shifting-issue-28791-2.html#post494055

Take if from him about your choice of oil.

I did thank you and I am returning the oil I bought....

I will match it with the manual requirements too....

 

[Nono76]

My finger is pointing at the screen. It is a bolt, O-ring and screen.

The manufacture is stating to check it while running. My truck tranny is the same way.

hello can you send me the manual in pdf
Twin disc MG 502 merci
arnaud51666@hotmail.fr

 

[Mischief Managed]

CAT TDTO 30 is perfect for TD transmissions.



I have a .pdf of the MG507 service manual. PM me with an email address and I'd be happy to send it.

 

[DDW]

hello can you send me the manual in pdf
Twin disc MG 502 merci
arnaud51666@hotmail.fr

Could just download it from Twin Disc?