Foam in Transmission Oil.

[George7941]

Vehicle is a 1999 Freightliner FL70 with a Eaton-Fuller FS6305A transmission.

I checked the oil level this morning by putting in my finger thru the fill hole on the side of the tranny and noticed a lot of foam in the oil on my finger. I tried it three times and found foam each time. The level was within an eight of an inch of the bottom of the fill hole and I added 100ml of oil.

Vehicle had sat for fifteen hours since last driven. Truck has 215k km (135k mi) and the tranny oil was replaced once at 110k km(70k mi). I used Shell Dentax 50 weight synthetic gear oil, approved for this tranny. This was five years ago and I never noticed any foam in the four previous times I checked the oil level (check it yearly).

The tranny leaks a little bit thru the rear seal, enough to contaminate the driveline-mounted parking brake shoes. The leak accounts for the 100 ml needed for topping up.

Why is the oil foaming? Should I replace it?

 

[Pablo]

Is water or other contamination possible?

Perhaps do a UOA.

I would change it regardless.

 

[MolaKule]

According to the Shell specs, this oil is an API GL-1 non-EP oilwith plenty of anti-foamant, so I would look for transmisson breather blockage or a breakdown of the oil's additive package, althought I cannot imagine the latter unless as Pablo, said, some kind of contamination.

You might want to try

http://www.amsoil.com/storefront/ctl.aspx

or

Schaeffer's

http://www.schaefferoil.com/742.html

 

[MolaKule]

Here's another spec for the Shell Dentax S:

http://2kwy.net/pds/pdf/DentaxS.pdf

It says it's an MT-1 HD transmission oil; this spec sheet says nothing about it being a GL-1, so I have to believe the oil is really has at least a GL4 EP additive package.

Here are the specs for a mineral oil version of the Dentax:

http://www.shellusserver.com/products/pdf/Dentax.pdf so it is this version that is a GL-1.

 

[JasonC]

Your tranny could have rabies

 

[MolaKule]

Try and put your sick humor down in the HUMOR section.

We're trying to help this person.

 

[sunfire]

Originally Posted By: George7941

Why is the oil foaming? Should I replace it?


Why don't you just change it? If it still foams then come back. 65k mi is a lot of miles to put an tranny fluid.

 

[mpersell]

Do you use the truck for a lot of short trips or work? Something in less than 10 minutes of less per use?

Foam is usually from water from condensation and not enough heat to evap or boil it out. If this was an engine and not a 5 speed we would recommend a hotter thermostat as a comparison. More than likely its a combination of a clogged vent or a seal letting in water and short term trips or hourly use.

If you can't find the source of contamination or a clogged vent then you'll probably want a more frequent change interval.

 

[George7941]

The truck is used in the city of Toronto for moving furniture and therefore sees a lot of stop and go driving. But it has done that all its life and there are other trucks doing similar duty and this is first time that I have seen foam.


"Why don't you just change it? If it still foams then come back. 65k mi is a lot of miles to put an tranny fluid."

I am definitely going to change it, especially since most of you advice it. I would like to find the cause first if I can. I am going to check for a clogged/disconnected breather tube. If I do not find an obvious cause then I will get a UOA done.

65k mi is not a lot of miles for a medium duty truck transmission and synthetic oil. In fact, Eaton-Fuller approves a 500k mi change interval for this tranny/oil, as can be seen at the Shell page that Molakule linked to, which was
http://2kwy.net/pds/pdf/DentaxS.pdf


George.

 

[meep]

I have seen PS fluid do this after my BIL drove (i.e., raced) my minivan 600 miles down I-81. Foamed up, blew out the cap, and the PS groaned, whined, and shuddered. I suspect it overheated the oil.

I flushed the fluid and never had the problem again. Never let him drive it again, either.

M

 

[onion]

Originally Posted By: George7941
Vehicle is a 1999 Freightliner FL70 with a Eaton-Fuller FS6305A transmission.

I checked the oil level this morning by putting in my finger thru the fill hole on the side of the tranny and noticed a lot of foam in the oil on my finger. I tried it three times and found foam each time. The level was within an eight of an inch of the bottom of the fill hole and I added 100ml of oil.

Vehicle had sat for fifteen hours since last driven. Truck has 215k km (135k mi) and the tranny oil was replaced once at 110k km(70k mi). I used Shell Dentax 50 weight synthetic gear oil, approved for this tranny. This was five years ago and I never noticed any foam in the four previous times I checked the oil level (check it yearly).

The tranny leaks a little bit thru the rear seal, enough to contaminate the driveline-mounted parking brake shoes. The leak accounts for the 100 ml needed for topping up.

Why is the oil foaming? Should I replace it?


Did you drive the truck across the lot and into the garage this morning before you checked the trans. oil level? If so, then that's why the oil is foamed- because you drove it.

Gear oil in a manual transmission foams to a point when the gears are turning. Unless your oil looks like cool-whip... this likely means nothing at all.

 

[George7941]

No, I did not move the truck. I checked it where it had been parked overnight.

 

[onion]

Then that's just plain odd.

 

[George7941]

Here is an update.

Took the fill plug off again today and there was no foam! This time, the vehicle had sat undisturbed for about 32 hours instead of the fifteen hours last time.

I will post the results of a UOA of this oil in about ten days.

 

[Doug Hillary]

Hi,
George7941 - It is important to continue to use an Approved lubricant in your transmission

Many people wrondly use an EP based gear lubricant (75W-90 and etc). Eaton-Fuller are very specific about this and a conforming synthetic SAE50 non EP based lubricant is the only one you should use - I speak with considerable experience in this area

Any such SAE50 Approved synthetic lubricant from Shell, Chevron, Mobil (Delvac), Castrol etc will perform very well indeed

I think the foaming will be shown via the UOA to be a non-event!

As to OCIs I ran 1m kms (620k miles) OCIs in my Eaton-Fuller RoadRanger transmissions (13, 15, 18 speeds) with outstanding results over many years. I used Delvac and Castrol products but I am very familiar with Shell's excellent gear train products too - going back 40 years or so

I look forward to seeing your UOA

 

[chief]

I agree with Doug Hillarys post. When I service my trucks we always run them down the road a few miles to get engine up to operating temp then pull them over the pit and pull the plug. If we check the trans and rear ends level as soon as the engine plug is pulled there is a slight layer of foam on the oils surface in both the trans and rear ends. The rear ends seems to have slightly more foam than the trans. If we go ahead and grease, check brakes, change fuel filters, check coolant condition, measure thread depth, and general inspection, then check the trans and rear end levels all the foam is gone. The only time I ever had a foam issue was when I let a jackleg salesman convince me to try an additive thats has been discussed on here before. After 5 hours the foam would still come out the check plug. Drained it out right there, foaming solved. My trans get Mystik synthetic SEA50 and the rears get Mystik synthetic SEA75-90, Oh no--flame shields up-- that dadgum Mystik, get he outta hear.

 

[George7941]

I got the UOA results, here they are

No water contamination. I will replace the oil. I also posted the results in the gear oil UOA forum. Here is the link

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1244154#Post1244154

 

[Doug Hillary]

Hi,
I have replied in the UOA section