Changing the Hydraulic Fluid

[Mike Canter]

Wow, what a surprise, when I unscrewed the hydraulic filter on my 2004 Signature for some reason I thought just a little hydraulic fluid would come out. I had no idea that it would drain the whole tank. That is a lot of fluid.

Can you confirm that I should be using Dextron III (now Dextron IV or Dextron/Mercon) as the hydraulic fluid? What came out was original from the factory and it sure didn't look like Dextron III. It seemed a little thicker and was not bright red it was brown in color. Could be just old and dirty.

[DtBt]

I don't know about your Sig for sure but my 99 Windsor and many others use AW-46 hydraulic fluid available at most auto stores for about $40 for a 5 gallon pail. My Windsor takes most of a 5 gallon pail when changing filters. It should be clearly labeled on reservoir what fluid it requires.

[Diplomat Don]

Mike...Read this post.....you most likely have oil in yours
Hydraulic Fluid Help

[walt2137]

Quote:

Originally Posted by Mike Canter Wow, what a surprise, when I unscrewed the hydraulic filter on my 2004 Signature for some reason I thought just a little hydraulic fluid would come out. I had no idea that it would drain the whole tank. That is a lot of fluid. Can you confirm that I should be using Dextron III (now Dextron IV or Dextron/Mercon) as the hydraulic fluid? What came out was original from the factory and it sure didn't look like Dextron III. It seemed a little thicker and was not bright red it was brown in color. Could be just old and dirty.

Probably AW 46 and I had to replace my fluid last year due to a CAC repair and found it at NAPA for under $30 then.

[Mike Canter]

Diplomat Don, thanks for that link but I am now confused more than ever. It is honey brown with a small tint of red. The book says I need to use Dexron III ATF. There is no sticker on the tank. I think I will wait before I fill it and call Monaco Tuesday.

This link says to use Dexron III in the 2004 Caymans and Diplomats
http://www.monacocoach.com/service/a..._reservoir.pdf


This link says to use Dexron III in the 2002 Sig with a hydraulic system like mine
http://www.monacocoach.com/service/a...lube_chart.pdf

This also says Dexron III
http://www.monacocoach.com/service/a...creservoir.pdf

I don't see any addendum that changes it fron Dexron III to anything else for a 2004 Sig.

I did find where a 2008 Sig Maintenance book it states to use Texaco Rando HD46 or if in 0*F weather use Pennzoil Artic Blue hydraulic fluid but I think that is a totally different hydraulic system than my 2004 Sig. I would think that if Monaco had a problem and changed the requirement for what type of fluid to use in a MH then they would list it in the Addendum website.

Confused

[walt2137]

Mike if the tank is empty you can use ether Dexron III or AW 46 one will work as good as the other, Dexron would be a better choice if you live up north as it about a SAE weight 8 or 10 and AW 46 is a SAE 15. if the oil has a yellow tent it is AW 46, Monaco used both at different times on different coaches.

[Twomed]

Mike sorry I didn't say anything about filter draining. My 06 is mounted higher, so there is no loss other than the filter amont. I do maintain an o3 with th elow mount, so I should have warned you , my bad! Both the 03 and mine have Dextron III, but I have seen units with the AW hyd oil. Since it is all out I would go with the ideas above re: weights and temp use for your coach.

Any other RR10 guys read and heed this thread. If your hyd filter is down low, bottom access, be ready for a real quick change, and getting some oil on you. The higher mounted one is straight in the engine compartment, easy screw of/on. AND as always there is probably some other Monaco config that will be different...ha..ha!!

[Mike Canter]

Let tell you when 14+ gallons start coming out you better have several buckets ready. It makes great hair conditioner reminded me of the Vitalis or Vaseline hair stuff from the 1960's .

I agree that it appears that the RR10 chassis in those years used the Dexron III and I haven't found any Monaco addendums online that change it. I don't know if what was in it was dirty Dexron III or the AV46. I believe that Monaco would have published an addendum if they had changed the requirement. I think I will still wait and call them Tuesday just to double check. I would hate to use 14 gallons of Dexron at $13 a gallon and find out they changed their minds.

[hardy1000]

Better to call Monaco with your coach number. My 07 Diplomat manual says Dexron but when I called Monaco to confirm they told me that I had 15-40 W oil and that is what I should use. When I changed the steering filter it was indeed oil.

[Diplomat Don]

I called Monaco to ask.....they said they used different fluids in different coaches. No definitive answer.

[c124driver]

Majority of hyd fluids are oil, depending on design conditions and cost and for RV manufacturers, cost is very important. The recomendations that some coach manuf make is to go to 15-40 oil in order to keep lubrication up as the operating temp is thining out the oil.

If you want the best and most consistant hyd fluid over a wide range of temperatures along with lower heat generation due to less friction, the answer is to use a synthetic oil such as Mobile one.

As an example, well know manufacturers of zero radius mowers (gas driven pump driving two hyd motors with very little cooling) stipulate mobile one synthetic or warrenty is voided.

As a retired wood products engineer, any time I had a heat problem due to transmitted hp close to design limitations I switched to synthetic lubrication and watched the temp drop.

So if your coach manufacture is asking you to go to higher viscosity motor oil to keep lubrication film and avoid catastrophic failure or shortened life, think about going to synthetic as its viscostiy stays constant over a huge temp range and maintains the lubrication film on moving parts.

That is why Allison reccomends transyd and Mobile delvac synthetic ATF is an authorized TES-295 replacement. Think synthetic for hyd fluid for lower temp and longer life of components.

No I don't sell but I have used in my vehicles and as plant engr for last 20 yrs and seen some amazing results.

Stan

[Mike Canter]

Thanks Stan. I agree with the synthetic fluids. Have been using Mobil 1 since the 1970's when it first came out and was rumored to destroy engines and seals. Use synthetic ATF in all my cars also.

I am waiting to hear from Monaco tomorrow to verify which fluid to use. Chhanging to a thicker viscosity than what the system was designed for can raise the pressure and ballon the hydraulic cooler.

One of the problems of using synthetic is the cost when I need 15 gallons of it. It is bad enough with regular ATF at $13.50 a gallon. I realize that synthetic can make thing last but I think in the case of my MH they want it changed every three years or 15,000 miles just to make sure no moisture is in the system. The Racor filter is a water absobing filter and if it gets too much moisture in it it will go into a bypass mode. I am not sure I want to experiment with leaving the synthetic fluids in for a longer period and cause $$$$ damage due to the moisture.

[Mike Canter]

This is what I have found out from Monaco via an email and via a phone call. Now this is just for a 2004 Signature. They say I can use AW46 or Dexron III. They used both in that MH. The only difference that I wiould notice is that if I was up north in the winter and it was getting cold like below 32* the the AW46 would thicken up and because of this the pressure would go up and may blow the hydraulic oil cooler. Since I drained it all out I have elected to use the Dexron III.

I have found out this while researching this issue. The 46 in AW46 is the viscosity.

If you use 10-40W oil as in some applications it has to be non detergent oil or it will foam and cause cavitation.

Thank you all for your help