Main Hydraulic Oil Change

[Edward Buker]

I thought that I would bring this subject up given I cannot recall much discussion regarding changing the hydraulic oil that runs the fan and power steering. My system may be due and my guess is that it probably has Dexron 3 in it but I am not sure. So the questions are:

1. How many people ever get this fluid changed and what do you use for fluid?

2. How often do you change it?

3. Anyone ever get a fluid analysis done to tell them when to change it?

4. What is the best practice to change the fluid and filter? Pump it out? Pull the filter and let it drain from the filter housing using some jury rig?

5. What is compatible with Dexron 3 that is available today?

I must admit in my last motorhome I went 10 years and never changed this fluid and it still looked good color wise and the fluid smell seemed normal. I did change the filter several times which was a plunge your hand in the reservoir cloth type filter. So this is one maintenance task I am not sure what is a good practice.

Later Ed

[Keith Moffett]

Ed, funny thing you should bring this up.  The maintenance list on our Pat said change that fluid every two years.  I have no idea when it was last done on the new coach but the filter has 2004 written on it.  I just bought 5 gal. of dextron (from a bulk oil company for about 1/2 the price of Walmart).  
There are a couple ways of changing this.  Yours is probably like ours a metal holding tank in the filter bay?  If so there should be a drain port with a recessed allen wrench (14MM).  I could not get this loose with a regular allen wrench but I am going after it again with a socket wrench mounted allen wrench tool.  I should be able to get enough on it to break it loose.
An option would be to pull the low pressure hose off (held on with just a screw clamp) but I am concerned that wa could get air in the line.
I am not concerned with changing all the fluid so I will not run the motor.  All new fluid at once might bugger up the old hoses and the radiator etc. so I will get the first 4 or 5 gallons this time and let the filter do the rest.  Then repeat in 2 years or so.
FYI:  I will have some teflon tape (plumbers tape) on hand as sealant for the threads on the drain plug as ours is in very tight ang the threads could be streatched.
Use a clean 5 gal. bucket and take the old up to OReilys auto for recycle.

Good Luck
Keith

[Keith Moffett]

Just a side bar Ed.
You have the same chassis we do I believe.  Steve at BCS showed me a detail the had been missed since the original lube at mfg.  There is a zerk fitting on the driver side of the steering box which is just inside the front driver tire.  If this goes dry it will affect your steering and wear the gears over time.  He put four shots of lube in ours and it made all the difference.
The zerk is small and hard to spot being black on black but worth looking for.
Change the power steer fluid and lube the zerk and waaa laaa! new coach!
Keith

[Gerald Farris]

Ed & Keith,
I changed the hydraulic fluid and filter using Dexron III in my coach on a 4 to 5 year cycle until the last time that I changed it. The last time I changed the fluid, I used Allison TranSynd instead of Dexron III because of its better lubricating properties and longer service life.

As for draining the hydraulic tank, just remove the filter and you have created about a 3/4 inch diameter drain that will empty the tank quickly. So if you want to change the filter without draining the entire tank, you had better be lighting fast.

Gerald  

[Edward Buker]

Thanks Keith and Gerald,

If I used the filter as a drain any idea how many gallons will drain? I also will probably go the TranSynd route and probably not change it again for as long as I own this coach. Gerald what did you jury rig to catch the oil, I was thinking maybe a piece of plastic gutter?

Keith, thanks for the zerk info on the steering box, I have not caught that one yet. Let me know how your drain goes with that allen plug.

Later Ed

[Gerald Farris]

Ed,
I used a piece from a liquid cattle feeder, but you probably do not have access to cattle feeding equipment there on the coast. From the best of my memory, which is not what it use to be, it took about three gallons of fluid.

Gerald

[Edward Buker]

Thanks Gerald. Your right, I do not have a cattle feeder hanging around but I do have my fair pile of man treasures lying around that I can jury rig something from. We did a shakedown trip to Destin last week and camped for a few days. Just the toilet ball seal was an issue so I changed that out.

We will be heading up to Vermont this summer. Hope all the BAC members are far away from this latest storm front. It has been a very active system so far. Safe travels to you and Glenda.

Later Ed

[Bill Borden]

Hi Ed,

Like Gerald I chose Transyn when I changed the fluid and filter, I believe that it did improved the steering response. Also Transyn (Synthetic fluid) reduces heat and friction, which reduces wear along with reducing the force required to pump the fluid.

  When I changed over to Transyn I  ran the motor with the return line to the reservoir disconnected.  With the return line disconnected I was able to flush all of the old fluid out.  Even though Transyn can be mix with Dextron.  It seem to be the right thing to do.  I just waited till the color of the fluid change.

Bill

[Edward Buker]

Hi Bill,

That seems like a good plan also. I will keep it in mind when I get to this job. May be fall given how things are going here.

Later Ed

[Keith Moffett]

Well, I gave Geralds filter method a chance but there is just no quick way to get the filter out on our coach.  We even had to remove the paper towel bucket cover just to finaly squeeze the filter out of its little corner pocket.  There would have been no way to collect the ATF.
The drain plug on the back side of the tank worked perfectly and there was room for  5 gallon bucket to catch the old oil.
The manual says any refill of the system (after the original factory fill) sholud take 5 gallons.  I was able to change 4 gallons without running the motor so I got a good level of clean ATF and a new filter.
Well, that's one thing off my list.

Keith

[Edward Buker]

Keith,

I had never seen that plug, I will have to go on the hunt.

Later Ed

[Keith Moffett]

Ed, our hydraulic fluid tank is the black metal one.  I imagine yours is too so the plug should be on the back side of the tank at the bottom.  It would be about the size of a quarter and have a recessed plug made to fit a 14mm allen wrench.  
I had to use a flashlight and a rag to find it because it iis black on black, dirty and in a dark area between a couple hoses.
Let me know if you find it.

Keith