Is GL-5 bad for our transmission

Discussion in 'Oil' started by ghost2277, Aug 12, 2010.

  1. ghost2277

    ghost2277 Member

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    I was reading around about transmission oils and I came across this link

    Does Gear Lube Corrode Yellow Metals

    probably need to copy and paste but anyways can someone please enlighten me a little further, I see alot of people recommending Spectro 6speed transmission oil and lots of other GL-5 rated oils but the mobil 1 site says its not good to use GL-5 rated oil in harley transmissions due to the corrosion of "yellow metals" like brass and copper..... Is there copper and brass or any other yellow metal in the transmission? I was going to buy mobil 1 75w90 gear oil cuz i heard it was not best to run 20w50 in the tranny, so i am confused I know you can run 20w50 in the tranny but its not the best option. anyways Could someone straighten me out? Oh and if your only reply is look in the oil section or something to that nature please do me a favor and don't reply. Thanks.
     
  2. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

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    I personally use the Spectro Heavy Duty Platinum 6-speed Transmission Oil in my SE 6-spd tranny. I installed this tranny on my '03 UC, and have been using the Spectro in it since installation. Here is what Spectro says about this product:

    Designed by Spectro in response to complaints from Harley owners about the great but noisy new 6-speed transmission, this full synthetic provides ultimate lubrication protection. Formulated to significantly reduce gear noise and provide easier, smoother shifting, this SAE 75w140 formulation eases shifting even when cold. High loads and extreme heat do not affect the oil, so it performs well when pushed hard and long. A.P.I. GL-5 rated

    However, if you are worried about it, they also have a GL-1 rated FULL synthetic gear lube in both 75W90 and 75W140.

    TQ
     
  3. ghost2277

    ghost2277 Member

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    I appreciate the reply, I am guessing this is a problem that would take a long time to manifest, I know there are alot of people that use GL-5 rate gear oil, because from the posts I have read they do quiet down the tranny but I was hoping some mechanics could chime in and enlighten me if we actually have any "yellow metals" in the transmission, if we don't then its a non issue. I have never tore apart a harley tranny so I have no idea what metal is used in the tranny.
     
  4. Jack Klarich

    Jack Klarich Expert Member

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    GL5 in my tranny, no problems:s
     
  5. jdeatsch

    jdeatsch Member

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    From the techs at Pennzoil/Shell/Quaker State:

    Dear Mr. Jim;

    Thank you for your interest in our products. You are correct the GL-5 oil has twice as much of the anti-wear compounds as the GL-4. These compounds contain sulfur and phosphorous which will attack yellow metals such as brass, bronze and copper.

    Sincerely
    Product Technical Service
    Pennzoil Oils, Shell Oil Company
     
  6. Iceman24

    Iceman24 Well-Known Member

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    +++ Spectro 6-speed all the way...got mine on sale at DennisKirk so even better!
     
  7. 09RGlideKY

    09RGlideKY Active Member

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    I Believe you only have to worrry about yellow metals in transmissions with synchronizers' I heard that Harley's didn't have them but I could be wrong. I had some sport bikes that did.
     
  8. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

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    I wrote to Spectro asking them the exact same question as that asked on the Mobil site. Here is their response:

    Our Platinum synthetic gear oils are GL-5, however the additive contains a component which mitigates against the yellow metal corrosion you mention. John

    John P. Dunne
    Spectro Oils of America
    Specialty Sales Manager/Private Label
    Tel # 203 775-1291
    Fax# 203 775-8720
    Cell# 203 770-4546


    TQ
     
  9. dangerdan

    dangerdan Junior Member

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    So the answere is yes. GL-5 does attack yellow metal, however Spectro has an additive which slows the process down.

    Mitagate - to make or become less severe or harsh; moderate
     
  10. jdeatsch

    jdeatsch Member

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    I just spent some time looking through the fsm for my 10 Dyna and I didn't see a synchro in the bunch of photos.

    That pretty much eliminates the yellow stuff I'd think.

    Someone who's actually had one apart can verify.

    Jim