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CASE zinc oil additive for hy-stsat

Doug B · 2026-07-23 14:18

Seeking any info--pictures, part number, specifications--on a vintage 1 quart oil additive sold by Case with their traditional Case Yellow markings. Probably from the 70s-80s-90s.

Replies20
  1. #1Coaldust2026-07-23 15:07

    Case Part # B17508.​ I’m looking around E-Bay, but I don’t see any of the vintage cans available. Viscosity Oil Company in IL was the blender.

  2. #2Ed ke6bnl2026-07-23 15:50

    Case does not have the additive. They recommend using 10W30 diesel. they claim that it meets the. Requirements that they had previously

  3. #3Doug B2026-07-23 16:18

    Do you know what was in it? I would assume it was a high zinc additive to be added to the early AW-32 to better protect the high pressure piston pumps in the hy-stat drives? High zinc break-in motor oil from NAPA probably the closest thing that's available now?

  4. #4Deere500a2026-07-23 16:30

    Cnh site may have it. Old Hamilton auction

  5. #5Deere500a2026-07-23 16:33
  6. #6Coaldust2026-07-23 19:56

    ZDDP Base oil 20wt SAE Phenol AO-1135 Antioxidant

  7. #7willie592026-07-23 22:19

    Since we're working with limited information, only know we're inquiring about Hy-Stat and Zinc in a Case hydrostat, have no clue which Case machine, no more information than that, then I say you nailed the formula right there Coaldust. Send it!

  8. #8Coaldust2026-07-24 00:38

    Yeah. For sure. I think the days of adding ZDDP to any modern oil is over. There are so many polar additives in modern lubricants competing for metal surface area. Adding more ZDDP on a whim is going to mess up the chemistry and create new problems. But, it’s fun to look back.

  9. #9HarleyHappy2026-07-24 11:50

    Meh, on my skid steer that uses motor oil for hydraulics, I still put in some ZDDP to make me feel better. Hasn’t blown up anything in a while.

  10. #10Nige2026-07-24 12:28

    All the more reason to use a purpose-blended hydraulic oil containing the appropriate additive package from the get-go. If that additive goes back almost 40 years there ought to be something just a hair better kicking around by now. Otherwise we would be, to quote my late grandfather, advancing backwards.

  11. #11willie592026-07-24 20:17

    I'm no chemist, but in theory I agree with Coaldust. Oil has changed. Just as engines have evolved, so has oil, so the oil requirements for a 2026 engine are not necessarily going to be the same as my 300/six in my '85 F150. Newer engines are pretty much all overhead cam, typically with rollers, whereas my engine is old school flat tappets, which SAE specs back in those days had some zinc in the oil for that. Newer spec oils don't. That's why I use 15W/40 Rotella in my 300, the diesel oil is closer to the oil spec for my engine.

  12. #12DDoug2026-07-24 21:36

    I never did figure out what Pennzoil meant on the can "Now with Z-7". Was on the side of the tanks at the refinery in Rouseville as well.....

  13. #13Doug B2026-07-25 01:07

    Roger that. Google says the Rotella is 1200ppm, and Valvoline VR1 racing oil 1200-1400ppm, which is about where most of the brand name motor oils were at in the 60s & 70s . I don't know how much zinc was in the typical hydraulic oils of the era (such as Chevron AW32), but I know at least one equipment manufacturer (Clark/Bobcat) recommended engine oil as suitable for hydraulic in their hy-stat skid-steers. No doubt because the high pressure sliding action of the variable displacement piston pumps lived longer with the high zinc content. Most modern hydraulic oils have much less zinc content. The high-end Cat HYDO has 1200ppm, but it's $175 for a 5 gallon bucket. The Lucas TB Zinc-Plus break-in additive I picked up today ($20.30) has 43000ppm (4.3%). Mixed 32:1 should be about right at 1344ppm. ​

  14. #14Doug B2026-07-25 01:15

    Actually we do advance backwards rather frequently. They drastically reduced the ZDDP in motor oil because it was killing the catalytic converters. And they have been taking it out of hydraulic oil now because of "environmental concerns". There's a long list of products that were very effective back in the day, that have since been regulated out of existence or outright banned altogether.

  15. #15Doug B2026-07-25 01:25

    And ZDDP

  16. #16KSSS2026-07-27 09:41

    HTO additive was a thing in the 1840-45 machines. The machines newer than that never called for it, as my memory tells me. It just speced 10-30. The newest machines now spec HV64.

  17. #17Nige2026-07-27 11:58

    We'll have to agree to disagree in that case. I'd take today's oils, correctly specced for the application of course, over stuff from 40 years ago in a heartbeat. In regard to hydraulic oils, unless they have an ashless/zinc-free additive package most quality oils these days are north of 500ppm on zinc.

  18. #18Tyler d4c2026-07-27 13:23

    Im going to make this problem stupid simple Go get your favorate flavor of hydro trans oil. Be it mobile 424 hygard or hytran and dump it on in there. It will be fine. Its a old machine the best oil of that day is worse then the cheapest oil of today.

  19. #19Doug B2026-07-27 15:33

    I found a 7 yr old post on Skid Steer Forum that said "1845c prior to serial JAF0067438 used axial piston drive motors and planetaries. They do not need HTO additive. After JAF0067438 they used gerotor drive motors and no planetaries. They use HTO additive to prevent wear in drive motors." But that sounds backwards to me Maybe he just inadvertently flipped it? My understanding was that the pump manufacturers (40-50 yrs ago) all spec'd high zinc oil for their piston pumps and piston motors, whereas gerotor motors are just fine without it. BUT don't you still have axial piston pumps in there to run the drive motors??

  20. #20KSSS2026-07-27 16:50

    I don't remember needing HTO after the 1800 series. The XT series came out in like 1999 I believe. I could also be mistaken. I know we used that during the 1800 series. The logo on the HTO bottles is pre 1995. So the 1800 series would have been the only machines that would have used it.