Differentials.. 75w-90 vs 75w-110

Discussion in 'Towing' started by mistaake, Nov 29, 2018.

  1. mistaake

    mistaake Real Name: Michael

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    I want to switch to AMSOIL Severe Gear in both the front and rear diffs. I don't tow or haul with my truck frequently, but I might be installing a camper shell and heavy toolbox, and I might tow (rarely) in the future.

    It seems like the ideal solution would be 75w-90 in the front diff and 75w-90 in the rear diff, but I'm wondering if I could get away with 75w-90 all the way around for the sake of only buying one type of gear oil.

    What viscosity do y'all run? Thanks!
     
  2. 454cid

    454cid I'm Awesome

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    Synthetic 75w90 is OEM after early 99... go with that. 110? Never heard of it.

    Also edit your post, you typed the same weight everywhere.
     
  3. df2x4

    df2x4 Domestics only.

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    Not sure why you're wanting to switch honestly. Not saying Amsoil makes a bad product or anything but non-synthetic ACDelco GL5 80W-90 has done just fine in both of my trucks. It's what GM recommends for these. Granted I don't tow much at all but I beat the everloving crap out of the ten bolts, and the one in my red truck ran the original gear oil for almost 80K miles before I finally had it changed if I remember correctly. G80 still works. (Knock on wood)

    Here's a link, I run this in both of my trucks. Front and rear in the Suburban. NO friction modifier! Very important to make sure you're using gear oil that doesn't include any if you have a G80.

    https://www.amazon.com/gp/product/B007Q10F3S
     
  4. 454cid

    454cid I'm Awesome

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    That's expensive for less than a quart.

    I think some of the gear oil in my truck is older than the truck... stuff that my uncle has stored under his workbench. I was running out of what I had left of my 2 gallon jug from TSC.
     
  5. Supercharged111

    Supercharged111 I'm Awesome

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    I've long wanted to take the plunge to synthetic myself as it flows better in cold weather. My mpg drops noticeably in the winter and my right foot can feel the increased drag. I would stick with the stock weight, or as close as possible. Based on your usage triple digit viscosities would be a waste.
     
  6. mistaake

    mistaake Real Name: Michael

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    Sorry, I do see I made that typo. And thank you I'll just buy 75w-90 all the way around for simplicity's sake.
     

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