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What Types Of Gear Oil Used In 1967 Cj-5?

Discussion in 'Early CJ5 and CJ6 Tech' started by cj51967, Nov 21, 2016.

  1. Nov 21, 2016
    cj51967

    cj51967 New Member

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    What type of gear oil is used in the 1967 Kaiser Jeep CJ-5 transmission, transfer case, rear differential, front differential, and steering knuckles?

    Is it all 90 weight gear oil? I know nothing about oil, so let me ask what types of 90 weight gear oil are there and which ones can I used in my Jeep? (synthetic?, mineral?, any other types????). I've seen descriptions on some of the bottles such as GL-1, GL-2,....,GL-5, etc What do those means and which ones should I use on my Jeep?
     
  2. Nov 21, 2016
    Focker

    Focker That's a terrible idea...What time? Staff Member 2021 Sponsor 2020 Sponsor

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  3. Nov 21, 2016
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2021 Sponsor 2020 Sponsor

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    Original spec was 80/90 SAE. Do not use GL-5. Even when they tell you it is the "same."

    Search the archive for Knuckle Pudding, or 'corn head grease.'

    And with apologies to Howard…
    Buy an FSM or we''ll kill the dog.
     
  4. Nov 28, 2016
    cj51967

    cj51967 New Member

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    I read the oil threads you guys pointed me to. I think I know what to use now, but I'm not 100% sure because there was more than one opinion on what to use where and also some of the postings seemed a little ambiguous plus it is possible that there is now newer information that might be different.

    So, I still have a few questions and would be grateful to anyone who can help out so I can try to understand all of this.

    True or false that 80/90 weight gear oil comes in the following versions: gl1, gl2, gl3, gl4, and gl5?

    True or false, I should use only 80/90 weight gl5 oil in the front and rear differentials and in the transfer case because the gl1,gl2,gl3,and gl4 versions don't protect as much? If false, what should I use instead and where? Wherever it is ok to use it, I prefer to use 80/90 gl1 because it is easy for me to buy since my local napa stocks it and it is also cheaper than any of the other gear oils I can buy locally.

    True or false, I should not use 80/90 weight gl5 in my t86 transmission because it will damage the synchromesh mechanism that is used for 2nd and 3rd gears? Just want to see if people still agree with this.

    In my t86 transmission, can I also use 80/90 gl1, 80/90 gl2, and 80/90 gl3 instead of 80/90 gl4?

    True or false, in the steering knuckles I can use a mixture of gl5 and grease where the grease is added to thicken it up into a "pudding" so it won't leak out as fast? If not, what do you recommend I use?
     
  5. Nov 28, 2016
    Focker

    Focker That's a terrible idea...What time? Staff Member 2021 Sponsor 2020 Sponsor

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    Here's another found in the Technical Index section. It may just add to the confusion?

    Syncromesh
     
  6. Nov 28, 2016
    Focker

    Focker That's a terrible idea...What time? Staff Member 2021 Sponsor 2020 Sponsor

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    tcfeet likes this.
  7. Nov 28, 2016
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2021 Sponsor 2020 Sponsor

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    Daryl likes this.
  8. Nov 28, 2016
    timgr

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    Ok, if you go to WalMart and buy their gallon jug of gear oil, it will be GL-5. Likely the bottle will claim that it's GL-4 compatible.

    Modern oils are labeled differently, so 85W90 gear oil is the replacement for 90 wt, and 85W140 is 140 wt.

    Forget GL-1, GL-2 and GL-3. You will either use the 85W90 GL-5 oil and accept that it's ok when GL-4 is called for, or you will buy GL-4 oil and use that for manual transmissions only.

    The GL-5 is perfectly fine for axles. Add friction modifier if it's a limited slip axle. If you buy GL-4, you will only use it in your transmission.

    Personally, I do buy the gallon jug at WalMart. I put it in my axles, and for the past year or so I have bought the gallon bottles of StaLube GL-4 from Amazon for my Jeep manual transmissions (see PeteL's link).
     
  9. Nov 28, 2016
    colojeepguy

    colojeepguy Colorado Springs

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  10. Nov 28, 2016
    cj51967

    cj51967 New Member

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    Thanks.

    Timgr: Did 1967 CJ-5s offer a limited slip differential as original equipment? How can I tell if my differentials are limited slip (hopefully without having to open up the case and look inside)? Could limited slip differentials also be used on the front wheels too? I'll have to look because I don't remember if there are any metal tags on them or if so, if they haven't corroded to the point where they can't be read.

    Can I use gl5 in the transfer case? I would imagine the transfer case has no limited slip components or synchromesh components and so gl5 should be what it takes, do you agree?

    I have to admit that I've owned and driven my 1967 for 43 years and I used to just buy anything called gear oil and put it into everything that took gear oil on average maybe about once every 10 years at best and my Jeep has run great the whole time even if the differentials/xmission/xfer case/knuckles were probably dry or close to dry most of the time.

    I also once got stuck at high tide and drove my Jeep mostly underwater and never once did anything special to it after that either and that happened about 40 years ago.

    So, sometimes I wonder if doing maintenance is over-rated!
     
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  11. Nov 28, 2016
    timgr

    timgr We stand on the shoulders of giants. 2021 Sponsor 2020 Sponsor

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    Yes, sure. There should be a tag under one of the cover bolts. Not on the front from the factory, but a previous owner could have installed one. Buy the gaskets and look under the covers, if you have not. Easiest way to change the oil.

    No, if you have a three-speed, the transmission and transfer case share oil.

    It's not about the limited slip issues, it's about the character of the oil. Read the posts at the links given above to learn more.

    Up to you ... you asked advice and it was given.
     
    Last edited: Nov 28, 2016
  12. Nov 28, 2016
    cj51967

    cj51967 New Member

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    Thanks. I think I'll do exactly that, buy gaskets and open up differentials and look inside & change all the oil.

    Not sure I would know what a limited slip looks like so if anyone can point me to photos of the ones that might possibly be present on my Jeep, that would be great. Otherwise, when I open up my differentials, I'll post photos here and ask if anyone thinks my differentials have limited slip.
     
  13. Nov 28, 2016
    PeteL

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    Jack up one wheel and try to spin it with TC/transmission in neutral. If it turns easy you don't have limited slip.
     
  14. Nov 30, 2016
    cj51967

    cj51967 New Member

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    With both rear wheels jacked up, I can spin one of the wheels using just one finger and my wrist, almost no effort at all required. But when I drop only one of the wheels down to the ground, I can no longer spin the other wheel with one finger. However, I can spin it by putting my palm on the tire circumference and pushing on the wheel with just one arm. I'm not good at guessing, but I'll guess anyway that on the tire treads I was pushing with about 20 to 30 pounds of force. It was definitely more effort to spin the wheel when the other wheel was on the ground, but on the other hand, I didn't exactly have to kill myself to spin the free wheel when the other wheel was on the ground. If the amount of force I had to use with my arm is a measure of how much force will spin one grounded wheel when the other wheel is spinning, such as when it is on ice, then I don't think that amount of force is going to do very much to move the vehicle when one wheel is spinning on ice.

    Also, for what it is worth, the existing gear oil in this differential probably has no limited slip additive in it and I already topped it off with new 80/90 gl-5 gear oil (but if necessary to add friction modifiers, I can probably get a little back out to make room for putting in the friction modifier).

    Based on that, do you think I have limited slip in my differential?

    EDIT: When I spun the wheel around manually, the driveshaft was not locked. When I did the same test, again driveshaft not locked, on the front differential, the 2 wheels spun in opposite directions unlike the rear differential where they spun in the same directions.

    What is the stuff I should add to the rear differential gear oil because it has limited slip and do you know where I can buy it?
     
    Last edited: Dec 5, 2016
  15. Nov 30, 2016
    PeteL

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    Do you mean only one wheel spins when both are jacked up?
    I'm out of my depth here.

    Maybe someone who knows more about the different types can tell you.
     
  16. Nov 30, 2016
    cj51967

    cj51967 New Member

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    When both wheels were jacked up, the wheel I tried to spin by hand turned super easy while I used only my wrist and one finger to spin it. This did cause the wheel on the other side to also spin.

    I was just pointing out that it took a lot more force to spin the wheel when the other wheel was on the ground than when the other wheel was also jacked up. Maybe someone who knows more about this then I do can tell if that rear differential has limited slip or not. For all I know, it does which would explain why it was easier to spin a wheel with the other wheel jacked up instead of being on the ground and quite possibly my limited slip has degraded (after all, it is now 49 years old and may not have had proper lubrication for long periods of time too) and that might explain why the amount of force it takes for me to turn a wheel with the other wheel on the ground is still not very much. I'm just guessing here, I know nothing for sure.

    At some point I will take off the covers of both front and rear differentials and look inside and try to figure out if there is a limited slip there. If there is not or if it is not working right, I'll look into either fixing it or adding something to increase the traction when I plow snow in my driveway (I've heard of something called "lockers", maybe they would do that?).
     
  17. Dec 1, 2016
    PeteL

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    If both wheels spun in the same direction, that suggests you have limited slip. Also the fact it took "a lot more force" when one was on the ground.

    Trying it in gear would confirm.

    I do believe the clutch pack in some types can indeed wear out.
     
  18. Dec 1, 2016
    timgr

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    Well, the factory would have supplied the Dana PowerLock in 1967, and it is unlikely to wear out to the point where you can turn the wheels against the clutches.

    If you put plain oil in a LSD, the axle will chatter as you go around corners.

    When you turn the rear wheel, the motion has to go somewhere. It is important to lock the driveshaft by placing the transmission and transfer case in gear, so that the rear driveshaft cannot turn. If the transmission is in neutral, either the opposite wheel or the driveshaft can turn, and your test result is not definitive.

    With the driveshaft locked, and both rear wheels off the ground, turn one rear wheel. If the opposite wheel turns in the same direction, it's a LSD (limited slip differential) or a locking differential (locker). If the opposite wheel turns the opposite direction, it's very likely an open differential (ie a conventional differential).

    There is a lot on the internet about this topic. If you can't figure this out from this description and a little internet reading, take a picture of what you have.

    The only 100% certain way to know what you have is to take the cover off and look. Are you being deliberately contrary? - just do it, or pay somebody to do it - it's a 15 minute job at the most.
     
  19. Dec 1, 2016
    Dave B

    Dave B Frankenjeep '67

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  20. Dec 1, 2016
    PeteL

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    Sincere question -
    I'm sorry - I don't understand how the wheels can both turn in the same direction if the driveshaft is not moving. ??? Unless both clutch packs are slipping? Can that happen with a "locking" diff?
     
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