Mixing Hydraulic fluids

[Georgia Mike]

I am in the midst of changing my hydraulic filter. Above the hydraulic tank there is a sticker that says Use Texaco Ursa 15w40. When I pull a sample it’s definitely not super red like atf but I think atf has been added. The reason I why I think that is because when I purchased it two years ago there was a gallon jug half full of Dexron three in rear bay and being since I have Transynd in the transmission I don’t know why else it would be on board. I like to prefill my filters so is it ok to mix atf with this oil. At this point I’m not sure if it’s oil or aw46 in there. 

[klcdenver]

the 15w-40 is actually motor oil not ATF.

[jacwjames]

I looked at your manual.  Page 359 says the hydraulic fluid should be Dexron III. 

If in doubt I'd drain and refill.  It will be hard to get all the old fluid out but you'll get +90%.

[Jim Pratten]

20 minutes ago, jacwjames said:

If in doubt I'd drain and refill.  It will be hard to get all the old fluid out  but you'll get +90%.

Ideally, someone very knowledgeable and experienced (preferably a chemist), will speak up and say all those fluids are fine to mix in any ratio.  Otherwise, I would also drain and refill.

 

[96 EVO]

Don't know if you have read any previous threads on this subject, but, Monaco was 'all over the map' on what their manuals said was installed, and what was actually installed.

Could be ATF, Hyd fluid, or engine oil!

I even had one of their tech support tell me they would 'occasionally' add red dye to hyd fluid, before filling!

Like Jim said, you may be better off draining and starting over with fresh ATF!

[DavidL]

Well since there are two stickers with completely different fluids on the same label area, I wouldn't trust either.  Looks like ATF in your cup.

My guess is it has 15w40 in the motor and that's what that sticker is for.

Hydraulic fluid is generally ATF...consult the manual.

[Georgia Mike]

Thanks, I have read a lot of information on the site about the topic and I definitely would like to drain and refill but I’m getting ready to go on a trip and just wanted to change the filter right now and was just wondering if I could mix the fluids. It says in the manual this hydraulic tank holds 35 quarts…almost 9 gallons gezzz that’s a lot. I would like to put Transynd in but going to be pricey and even putting regular transmission fluid won’t be cheap either.

[96 EVO]

Do you have the restriction gauge on your filter head?

If that is staying in the green zone, I would probably leave things be till I could change fluid.

[Tom Cherry]

38 minutes ago, Georgia Mike said:

Thanks, I have read a lot of information on the site about the topic and I definitely would like to drain and refill but I’m getting ready to go on a trip and just wanted to change the filter right now and was just wondering if I could mix the fluids. It says in the manual this hydraulic tank holds 35 quarts…almost 9 gallons gezzz that’s a lot. I would like to put Transynd in but going to be pricey and even putting regular transmission fluid won’t be cheap either.

There have been many posts over the years.  I was changing mine and the Manual was DEAD wrong.  Called Monaco ..  They said the "tech writers" don't get down to the floor and don't know squat...that was in 2012 or so and the OLD TIMER tech supports were still working. I often wanted to say.....Maybe the Assemblers should look at what is in the specs and the manual and use that.

Bottom line, I had a pail of PURE Texaco AW 46 and my fluid was as RED as yours.  I called several folks...TRW, the Pump manufacturer, and some folks that I trusted that knew fluids....plus I had been in charge of maintenance at several different plants and we had a strict PM program for all of our molding machines with hydraulic fluid.

BOTTOM LINE....  You have, I believe, ATF. Mine said AW46.  AW46 AIN'T RED...it is yellow or straw colored... I pulled a sample from my NEW pail and it was NOT anywhere the color of my fluid.  Jim, the old time tech...said...we have NOT used Hydraulic Fluid since 2005 or so..  BUT, there were many 2008 Dynasties that DO have AW46.  No rhyme or reason.

MY RECOMMENDATION.  That fluid looks very RED.  IF IT WAS originally AW46, then someone did a GREAT JOB of draining and flushing and cleaning out the lines....as well as the pump and steering sector.

SO...  I would actually DRAIN the reservoir and replenish with Transynd.  The original (295) will work just as well. Mobil DELVAC 295 Equivalent is LICENSED by Allison.  It is the closest to the REAL Allison Transynd that you can find.

TRW told me that they had switched to TRANSYND as the required lubricant for their EXTENDED MILES WARRANTY and servicing.

If you drain the reservoir and I don't know if you have the 5 gallon (most likely) of the smaller 2 gallon (like my 2009 Camelot), then do that.  I would PUMP or syphon it out....not break a fitting.  Then replenish with Transynd or equivalent and NEVER TOUCH IT AGAIN. I am on my second filter change and don't intend to ever do it again.  I have around 70K and it will be great decades from now.

That's my take....

BTW... I have the smaller reservoir with only ONE filter and I have a spin on Hydraulic filter with the gauge on top. If you have THREE filters, you have the larger reservoir, SO if you drain it, you will have a HIGHER Percentage or Concentration of NEW CLEAN TRANSYND...  That will last longer than you keep the MH...or my guess. 

[klcdenver]

You have misread the quantity it is only 3.5 quarts. I have been thru this when I changed my Sheppard steering box to a TRW.  If it is not broke don't fix it just refill with 15w-40 and keep going, it appears it has been working for 18 years now.

[Tom Cherry]

10 minutes ago, klcdenver said:

You have misread the quantity it is only 3.5 quarts. I have been thru this when I changed my Sheppard steering box to a TRW.  If it is not broke don't fix it just refill with 15w-40 and keep going, it appears it has been working for 18 years now.

I was answering the original question.  You have an EXCEPTION...and YES, I do remember it.  Your MH is an ELKHART assembly.  The Oregon Plant never used MOTOR OIL as a substitute for Hyrdraulic oil.  And that was ONLY a brief period.  If you read the manuals there were different.  WHY....WHO KNOWS.

The OP, @Georgia Mike has a 2006 Dynasty.  I THINK from talking to those owners...as well as looking at the picture where his dipstick is...he as the larger Reservoir or about 5 Gallons.  The 2 Gallon one is a ROUND one...which you probably have.  In your case, if you are happy with motor oil....drive on.

BUT, the question was about mixing and also what he has...so the information and comments were correct.

Hope this clears it up for you.

[Ivan K]

If your hydraulic tank looks like this, you would need 10 gal of Transynd to replace. An expensive proposition. 

[96 EVO]

31 minutes ago, klcdenver said:

  If it is not broke don't fix it just refill with 15w-40 and keep going, it appears it has been working for 18 years now.

I wouldn't do that!

I'm guessing (like others above), that 15w-40 sticker is what was put in the engine at the factory!

[Tom Cherry]

8 minutes ago, Ivan K said:

If your hydraulic tank looks like this, you would need 10 gal of Transynd to replace. An expensive proposition. 

iVAN,

Interesting.  I did NOT realize the Monaco used such a large reservoir in the early 2000's.  Most of the questions and comments were about the mid 2000's and I THOUGHT (my brain may be not a dependable as it once was) that there were TWO in use then.  Mine was the 2 gallon or so...ROUND.  The other was a bigger one and it was in the 5 gallon range...

OK....the Manual is WONDERFUL.  Pulled the OP's manual.

It DOES have a Hydraulic Spin on filter, I Googled the filter listed in the manual (CSG100P10A) and THAT IS a Spin on pressure filter. I DID think that there were THREE stacked filters INSIDE the cannister...but maybe not. Page 370 of manual

Capacity.  Initial FILL (entire system) 35 Quarts.  If you take 20 (my guess at 5 Gallons) from that, that leaves 15 Quarts or so in the total "plumbed" system. Page 269.

The OP can easily measure the size of his reservoir and do the math.

You may be right...but I just remember a smaller number.  Later on Monaco actually went to the 2 Gallon reservoirs on the 2007 or maybe 2008 or so...or at least that is what I thought I had been told when this was discussed many times before

[Jetjockey]

If your fluid level in not low and no known leaks, just go on your trip and resolve this to your satisfaction on your return . Likely it is dexron by appearance and the fact you had a partial jug from previous owner. That reservoir is the only place that likely could  use dexron on your rig..  If you have time you could have it sampled . Or take it to a transmission shop you trust for a visual opinion. Some of those guys see, smell and feel more than we can know. I would be much more concerned about a mixture of oils in your transmission than  I would this  power steering /hydraulic fan system . Good travels.

 

[Ivan K]

Just a curiosity from my manual. Sounds crazy to me especially since the filter is located below the tank with no factory installed valves and the seal is notoriously troublesome to install, impossible without draining the system...but it does have a pressure indicator so I go by that and stick with aw46, good for where we roam.

"Change the hydraulic oil filter every 15,500 miles or once a year. Total system capacity is approximately 46 quarts."

BTW, my slide hydraulics run on Dexron, so an other possibility. 

[Jetjockey]

41 minutes ago, Ivan K said:

Just a curiosity from my manual. Sounds crazy to me especially since the filter is located below the tank with no factory installed valves and the seal is notoriously troublesome to install, impossible without draining the system...but it does have a pressure indicator so I go by that and stick with aw46, good for where we roam.

"Change the hydraulic oil filter every 15,500 miles or once a year. Total system capacity is approximately 46 quarts."

BTW, my slide hydraulics run on Dexron, so an other possibility. 

Ah yes slides hydraulic slides. . Mine are electric but I do have hydraulic leveling leveling that is dexron .I had forgot that since I seldom use it. Having dexron in both systems may be a reason it is used to simplify the number of lubricants., 

[Ivylog]

Take a small amount of what’s in it and mix an even smaller amount of ATF in it. In 12 hours has it separated… I doubt it.

[Tom Cherry]

2 hours ago, Ivan K said:

Just a curiosity from my manual. Sounds crazy to me especially since the filter is located below the tank with no factory installed valves and the seal is notoriously troublesome to install, impossible without draining the system...but it does have a pressure indicator so I go by that and stick with aw46, good for where we roam.

"Change the hydraulic oil filter every 15,500 miles or once a year. Total system capacity is approximately 46 quarts."

BTW, my slide hydraulics run on Dexron, so an other possibility. 

If it ain’t broke…. Just be aware that you should never camp or drive the MH and park it overnight when the temps break ZERO. The AW46’s viscosity changes and it “expands”.  The typical damage is in the cooler and that be expensive.  That was why Monaco switched to ATF.  We usually have at least one failure or so per year.  BUT as there has not been the extreme cold that we usually get….no posts or “what do I do now?” The only “prevention” is to drive to a lower altitude or a spot where the minus temps are not forecast….

If one had a “big heating pad or an electric blanket”, might work.  Other option if you get stranded, do NOT SHUT OFF THE ENGINE.  Let it run all night and then drive on to a warmer clime.  

Yes, sounds crazy, but it was a major complaint and Monaco reacted with a fluid change.  If one can’t avoid the situation….and that includes storage, then biting the bullet and converting to ATF would be advisable and recommended.

14 minutes ago, Ivylog said:

Take a small amount of what’s in it and mix an even smaller amount of ATF in it. In 12 hours has it separated… I doubt it.

YES…. Most manufacturers do NOT recommed… but folks on the farm have been mixing motor oil, hydraulic oil and ATF for years.  My late FIL was a certified Flight Engineer in WWII and was awarded commendations for the “hours” he got out of his planes and was made an instructor.  

We had emergencies where we had to mix to get something working again,  I supervised maintenance and know my guys sometimes mixed different oils when there was none in stock and a machine was down.

TRC and my Pump manufacturer said, not good to do…but you may never have an issue…. BUT, based on the costs and potential damages, I’d stick to one type or convert to ATF. 

BUT….folks will do it and never have issues….just not for me. A pump or the DanFoss controller that regulates the fan speeds….and the issues with finding parts and then tearing down the system and the flushing…not worth the hassle and risk and cost. BUT each has to do what he thinks is right…

Just be aware of what the manufacturers say and then do as you please….at least you were informed…. Folks make those decisions all the time.

We Moderators have a policy to comment when comments are made about doing things that are not recommended by the experts or manufacturers is discussed.  So, this is just that comment so folks know…. 

[96 EVO]

4 hours ago, Ivan K said:

Just a curiosity from my manual. Sounds crazy to me especially since the filter is located below the tank with no factory installed valves and the seal is notoriously troublesome to install, impossible without draining the system...but it does have a pressure indicator so I go by that and stick with aw46, good for where we roam.

 

One thing they got right in later model years!

They mounted my spin-on hyd filter higher than the tank. Only got a few drips when I changed it 👍!

[Frank McElroy]

On 2/10/2024 at 8:54 AM, Georgia Mike said:

I am in the midst of changing my hydraulic filter. Above the hydraulic tank there is a sticker that says Use Texaco Ursa 15w40. When I pull a sample it’s definitely not super red like atf but I think atf has been added. The reason I why I think that is because when I purchased it two years ago there was a gallon jug half full of Dexron three in rear bay and being since I have Transynd in the transmission I don’t know why else it would be on board. I like to prefill my filters so is it ok to mix atf with this oil. At this point I’m not sure if it’s oil or aw46 in there. 

That 15w40 sticker was for the engine oil.  Your model year coach likely had AW46 hydraulic fluid in the hydraulic oil tank and that sticker is missing.  That straw color looks like AW46 too.  If you aren't traveling in below freezing weather you can stay with AW46 or change to ATF.  The two fluids are compatible with each other.

[Georgia Mike]

On 2/10/2024 at 2:45 PM, Ivan K said:

If your hydraulic tank looks like this, you would need 10 gal of Transynd to replace

Ivan, yes my tank is just like yours it huge so changing fluid is going to be expensive. Frank, yes I believe you are correct in that I have the AW46 fluid. When I pulled a sample and compared it to ATF it’s a lot lighter in color. I think ATF has been added over the years to top off. Glad to know it’s ok to mix the two. As others have suggested I’m just going to wait and change the fluid when I get back from my trip. Thanks for all the replies. 

 

[96 EVO]

Your money / your choice, but myself, I would just use a Dexron in the hydraulic system!

The pump has a pretty easy life, spinning a fan and a steering gearbox.

Edited February 12 by 96 EVO

[Jetjockey]

I was surprised to read here  that aw46 oil expands as it gets colder. I thought the viscosity increased as oil cooled and that expands at a rate of about 4% of volume per 100 degrees Fahrenheit as it heats. Transmissions and some other components are checked with oil at operating temperatures so the systems are not overfilled when checked on a cold reading. Anyone know for sure.

Edited February 12 by Jetjockey
Addit

[Tom Cherry]

6 hours ago, Jetjockey said:

I was surprised to read here  that aw46 oil expands as it gets colder. I thought the viscosity increased as oil cooled and that expands at a rate of about 4% of volume per 100 degrees Fahrenheit as it heats. Transmissions and some other components are checked with oil at operating temperatures so the systems are not overfilled when checked on a cold reading. Anyone know for sure.

I’ll let our resident Chemist, @Frank McElroy give you the scientific explanation… I just know it causes hydraulic failures and that is both a known fact as well as a demonstrated example.

Use the search function… two key word HYDRAULIC & FROZE or FROZEN.  I remember about 5 or 6 from the original Yahoo group that morphed into this and at least 3 or 4 instances here.  It is NOT a cheap repair and typically bursts the bottom of the radiator cluster and sometimes the pump.

Thus, my OMG, what do I do since It is gonna be subzero tonight?  If you google Hydraulic Oil or AW46 and Freezing, there is a lot of information.  There are special blends that were developed for Arctic & Antarctic expeditions….as most of their transporters have at least one or maybe two systems.

That’s all I know and the warning….as most folks don’t know or don’t think it happens.  This is not the same phenomenon as water freezing and expanding. Dr.McElroy has explained it here, a time or two…