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14 bolt FF fluid questions

Discussion in 'Differential & Driveline' started by AuroraGirl, May 3, 2020.

  1. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

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    Is this like the SM465 where i should use a very specific fluid? gear oil? Any recommendations on weight? I have a 14 bolt On my trailer(might remember an older thread) and I just took my slave axle shafts out of a spare 14 bolt and Im going to cut the shafts off so I can use the ends as covers. I feel bad wasting a good axle.. but i cant find the covers anywhere. The fluid that came out the differential smelled like motor oil and was black. That doesnt remind me of gear lube, at least from what I remember.

    Anywho,
    1) is the end washer/gasket a crush metal washer? Or can I reuse it? RTV?
    2) Do I need to flush the fluid and do a cover gasket? If so, recommendations on gasket, rtv, etc. otherwise can I just add fluid once installing my covers?
    3) if Im using the differential exclusively for a trailer, should i drain/fill the differential yearly like trailers repacking of bearings, or will it be fine for a while?
    4) Is a cover with a drain bolt a good investment?
    5) What fluid should I use?

    EDIT: Im going to use @bucket recommendation of jacking up one side and pouring fluid in. It seems gear lube(what weight?) is the choice?
     
    Last edited: May 3, 2020
  2. bucket

    bucket Super Moderator Staff Member

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    It takes 80w90 gear lube. There are paper gaskets, or you can just use a good oil-resistant RTV. Changing the lube every year seems excessive to me. But I'm lazy and go years without changing the gear lube in my trucks.
     
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  3. Blue Ox

    Blue Ox Turning Diesel Fuel Into Fun

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    Have you considered cutting a piece of approx 1/4" steel or aluminum plate and drilling it for the bolts to cover the hub ends instead of cutting up an axle. If it's just keeping the oil in it doesn't need to be fancy. You probably don't even need more than 4 bolts to seal it.
     
  4. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

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    Not a bad idea...do you think a stop sign with all 8.. or 6.. however many are on there.. bolts would seal sufficiently?
     
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  5. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

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    Because I could use the flange gasket that came off and I am ordering new ones to replace it.. I can use that to make my template with the bolt holes and the circle size.. and then throw my drill bits in the drill press and go to town. Might need a small hole saw at a certain point.. or just big drill bits. oh wait, I think the holes on flange are larger than bolts significantly, i could be wrong. either way, I could just step it out until my bolts fit through.
     
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  6. Blue Ox

    Blue Ox Turning Diesel Fuel Into Fun

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    You can probably get away with that and some silicone.

    If you have a big enough hole saw and a way of solidly securing the material in the drill press, hole saws cut really nice discs if you take the center drill out. But everything has to be locked down super secure to keep the saw from wandering or grabbing. A piece of sheet metal being spun by a drill press makes a nasty weapon.
     
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  7. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

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    i also have a marker and milwaukee tin electric tin snips. but i could buy a nice larger circlular hole saw, that would make it nice and even
     
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  8. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

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    Blue RTV silicone.. you think thats oil resistant? and heat? I cant imagine the fluid will be any hotter than the bearings will make it, so not outrageous given the surface area of the fluid. So I think blue rtv would be good on temperature. I Can get the black stuff, too. I got tubes upon tubes on the blue stuff, which I used for my intake and other coolant items. I am gonna go measure the axle flange and see if I can buy a hole saw in that size.
     
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  9. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

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    4.5 inch hole saw from milwaukee, ordered
     
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  10. Blue Ox

    Blue Ox Turning Diesel Fuel Into Fun

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    Blue Goo should be fine. When you assemble the cover, tighten the bolts to about 80% of the final torque. Let it sit overnight for the RTV to set up, then final torque it. That makes the RTV like a rubber gasket and puts it in compression. I've stopped a lot of leaks, like differential covers for example, by using that method.
     
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  11. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

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    Thats a great idea. Is there a torque spec or could just cranking it down work? I could get it tight then tighter the next day, but if torque wrench is advised I could go that route,, im sure the spec is the same across all the years.
     
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  12. Blue Ox

    Blue Ox Turning Diesel Fuel Into Fun

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    You're just holding a cover on, not handling all the torque that the drivetrain produces. So, snug to tight, then to tight or tighter. A torque wrench will help you get it all even, but I'd just pick something that feels right. No need to go to 100 lb/ft or whatever it calls for. Also, since you're not going to have as thick a flange to clamp, make sure the bolts don't bottom in the holes before it clamps the cover down. You may need to use shorter bolts or add some washers. Washers probably wouldn't be a bad idea anyway since the material you're using is a little on the thin side. They'll help spread the clamping force over a larger area.
     
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  13. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

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    Made a disc. Gonna drill holes in the morning. Learned how to operate a drill press and had to find out why the Chuck just kinda.. fell out. Got there. Note to self, snowmobile signs are thick.

    Also had to change the pulleys to get the RPM down to 200.. and the saw says to use about 80 rpm so I just kinda cut it in time segments of about 8 seconds, lift, add power steering fluid, cut, let it cool, cut, add ps, etc I think I over did it but I didn't want to wear out my hole saw on the first disc lmao.

    From my research and understanding, it's good that my differential is full float. If it had been semi float, I wouldn't want to bear a lot of weight on it without the shafts in. But in my trailer, it puts the weight across leaf springs and then the axle housing. And torque being the only force on the shafts.. there's nothing driving the differential! At least I'm understanding it this way.

    Another question, not related but curious if anyone has input. Would there be any benefit to reducing the leafs in my spring pack on the trailer? It's 56 inch 3/4 heavy duty springs(factory) the trailer unlikely carries more than 1000 pounds at max. But being a trailer it doesn't really matter how it bumps I suppose.
    Snapchat-1017816918.jpg
     
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  14. shiftpro

    shiftpro Full Access Member

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    Except that it will leave a hole in the center. The pilot hole for the hole saw...
     
  15. shiftpro

    shiftpro Full Access Member

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    Oh, never mind...
     

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