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Old 01-30-2014, 07:41 PM   #1
Join Date: Jul 2013
Posts: 45
Sub for ATF Type A for Hydraulic System

My slide out is stuck in a partially out position and I have hydraulic fluid in the pan under the system with a diminished amount of fluid in the reservoir. I've had two different people look at it and check the electrical components without any effect. The worst of the situation is that one of the three slide outs works. The other two don't. One of the jacks is partially extended. One of the so-called repairmen probably did that. The next thing I want to try is to add hydraulic fluid to the system to replace the spill--see if that fixes the immediate problem, but the Lippert manual says use Automatic Transmission Fluid Type A. Well...this doesn't exist. So, what can I substitute for ATF type A? My vehicle is the Georgetown 370xl, 2004. Any experience with this?

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Old 01-31-2014, 12:47 AM   #2
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You can use Ford's Mercon V,Gm's Dexron III.

2012 Palomino Ultralite T245
2004 F250 Supercab 5.4L
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Old 01-31-2014, 12:56 AM   #3
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Thank you. I'll run down and get some of this tomorrow. I expect that's only the beginning: I'll need to find the source of the leak next, as well as, hope that it solves my slide out problem.
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Old 03-04-2015, 10:11 PM   #4
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I have a 2002 Cardinal 29f 5th wheel. I had a issue with my slide outs. I have a Dewald Hydraulic system. On the tag on the pump it says to use ATF fluid but the owners manual says to use 10W Hydraulic oil. In talking to the Lippert Components tech, I was told that I could add ATF to my system. When I contacted the company and questioned the discrepancy, I was told that any ATF that was in my hydraulic system had to be flushed out. I am not done dealing with Lippert and this issue I wanted you to know about this.

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Old 03-05-2015, 01:10 PM   #5
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From experience working with hydraulic systems. Number 1 would be that you follow the instructions from either the hydraulic pump manufacturer or the hydraulic cylinder manufacturer. Some hydraulic systems I have worked on state, very plainly, NOT to use ATF (automatic trans mission fluid) because of the additives within the ATF fluid. Some, but not all, additives within ATF could/can/most likely will cause seal failure when used on hydraulic systems. ME--IF this were my unit with a hydraulic system to operate the slide cylinders: I would use a good brand of hydraulic oil which should be either a 5W or a 10 W oil specifically for hydraulic systems. I don't know if an RV slide hydraulic system has a fluid filter on it or not, but IF it were mine and it did not have a filter I would find a way to install one. I know we are talking here about RV slide systems which operate intermittently and industrial hydraulic systems which operate 24/7/365 but--clean hydraulic oil will make a system last longer.
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Old 05-20-2018, 08:08 PM   #6
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Long time has passed to reply to this thread, but I believe I have the same pump as rnrhunter and am hoping he will see and understand this - I have a 2002 Montana with a LR slide stuck out. The first thing the Dewald hydraulic manual says is if the slide starts to move and stops check the fluid. I just cannot understand how you do that. Mine does not look anything like the picture they show. How do you check it?

There is a big textured knob on the top right that says it is a (4) "breather cap". There are two knob-y cap-type things on the front left side above the IN/OUT button - one is 6-sided gold and one is silver and mostly round with a flat-sided bottom. On top there are at least 6 holey things; two of them have black lines attached that go in two directions, I assume those are the hydraulic lines. (There are two slides - the bedroom retracted fine and the LR one hung up after 3 inches and wouldn't move either direction although the motor was still running). do you "check" the fluid? Maybe their drawing is not the front view but the top down view - but they say "1. leave the red plastic cap in Port "B" (rear port)" - and I have no red plastic cap. I have fittings and lines front and back on what I'm guessing is an aluminum body. you disconnect the fittings and lines first? are you then pulling the whole cylinder apart? That's what the directions sound like. "Fill tank to within 1/2" of the top; extend the cylinder NO MORE THAN 1 FT. Refill, extend, etc.") I have never been so baffled by directions manufactured in the states. There is certainly no sign it has leaked out - there, anyway, but it's been sitting like that for -4.5 years (yeah, a long time and I have never thought to just move it to exercise it).

PS - The manual says "use any type automatic transmission fluid as directed on the sticker, you can mix with hydraulic fluids with no adverse effects". FWIW.

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