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Hydraulic oil or ATF?

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Welder Dave

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It's probably been asked before but can Dexron III be mixed with hydraulic fluid? My new to me grader specifies Dexron II which is no longer available but Dexron III is supposed to be backward compatible with it. I don't know what fluid is currently in the reservoir but added about 1 1/2 litres of Dexron III I had. I bought another gallon of Dexron III but am wondering if it would cause any problems if hyd. oil was in the reservoir instead of Dexron? From what I've found elsewhere, it shouldn't be a problem but thought I'd ask the experts on here.
 
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skata

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I've looked into this before and from what I concluded, dexron is basically hydraulic fluid, but it has a lot more additives and has a lot wider temperature range, compared to standard hydraulic oil.
 
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Welder Dave

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That's kind of what I thought, that Dexron is basically a high grade hyd. oil. Impossible to know what has been added over the years is why I'm asking. It's not a real high tech. hyd. system like some new equipment has. Just gear pumps I think and have read they aren't too fussy. Don't want to dump a bunch of oil needlessly.
 
Flat Thunder Channel

Flat Thunder Channel

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I never looked into this before, but it makes sense. I guess I would just keep adding the correct ATF fluid. Probably would only do a full dump and change if the oil looked weird and or if it experienced operating issues.

I have seen hydraulic fluid with a red tint before. I wonder if that fluid is closer to ATF than traditional hydro fluid? Oil manufacturers and specifications sometimes it's all a big sales pitch/game. I tend to get confused by all their different specifications.
 
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skata

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Was the fluid in the tank, red? Then more than likely it was a trans fluid like dexron.
 
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cuttin edge

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Finish grader operator
Your machine must have a different transmission than mine had. Mine had a 10W oil. I had 2 selectors, a forward and reverse, then a gear selector that I had to manually pulse to shift up or down, with that stupid indicator that you couldn't see. There were 2 plugs on the side of it, a fill plug, and a sight glass. I know the older ones with the detroit had atf, but not mine. Mine also had a clutch attached to the back of the motor with a shaft going to the transmission.
 
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Welder Dave

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This oil is for the hydraulics not the trans. The machine has the 8400 transmission but being a series II (84-88, 1st to use the 8400 trans.) lists the original trans. oil as Dexron II. I read a service bulletin somewhere on the net that said Champion was recommending changing to 10W trans. oil because the Dexron II would cause the trans. to slip in some circumstances. The series III that came out in 89 does specify 10W for the trans. I'd have to look to see if the series III still specified Dexron for the hydraulics. In a weird way I'm glad the gear indicator is next to impossible to read. I take it's a common problem but doesn't mean there is anything wrong with the trans. Having it hard to read doesn't mean you have an expensive repair to the trans. coming.
 
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cuttin edge

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It's only been 10 years, but I can't remember what she had for hydraulic oil. It wasn't ATF though.
 
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Welder Dave

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There's a sister machine to that for parts at the RB sale. Same year too. It's an early series III. Mine is similar but there are a few differences on the series II machines. Thanks for posting that, it makes me feel I got a good deal at $15,500 delivered to my property. If I get the tires at the auction, I'll be similar condition for a lot less than $34,000. I can replace a door window and fix the seat for not too much too.
 
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chidog

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kent, wa
If its the hydraulic system then I would drain it and fill with hydraulic oil. In a transmission the use of Type A that later became Dexron, was in those days, GM specific fluid and was always known to be slipperier than Type F the fluid used in Fordomatics of the day. I think in the old racing days some used type F for firmer shifts. The friction modifiers have always been to allow for some slippage before clutch pack lock up, for smooth shifts, as that was the big goal of Automatic transmission designers of the day, to make the shifts barely noticeable. Kinda like the now CVT days.
 
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Tenwheeler

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Some equipment I work on the customer requires ATF. Says it is more environmentally friendly if leaked.
 
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