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Need some help with my rear differential

Discussion in 'Differential & Driveline' started by yepyep, May 8, 2021.

  1. yepyep

    yepyep Junior Member

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    hey all im looking to get some advise ill try to keep it short

    bought an 87 v20 project truck 2 years ago been slowly plugging away at restoring it. truck came with a spare rear diff thats in much better shape then the one in the truck

    hauled out the old rear went to install the new one and no dice its a 373 going off ring gear one that was in the truck was a 410 they are both 14 bolts. I have looked for a week cant find a 410 in my area...is it worth the time and effort to swap the guts from one to the other?

    another thing to note I would like to post a pic of the front axle so you guys can see it I never put the truck in 4wd so im assuming it matches the 410 rear but im not positive

    front diff pic attached but thats not my main issue right now

    PXL_20210506_212800251.jpg
     
  2. bucket

    bucket Super Moderator Staff Member

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    That's a 10-bolt front, but that's all that can be deciphered in the pic.

    What is wrong with the original rear axle? I'm assuming it's the 9.5" 14 bolt rear axle? I don't know of any K20's that came with a 10.5" rear after '80.
     
  3. yepyep

    yepyep Junior Member

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    its rusted beyond repair heres a pic of the rear ends you probly cant tell but the orginal has very deep rust pits housing is so rusted im not sure how it holds oil and hardly anything left of the brakes other then that it does work and internally it looks good.

    fyi im not used to messing with differential s and im kind of a weekend warrior heres some pics what size rear diffs are these 9.5s or 10s? PXL_20210506_220730294.jpg PXL_20210506_203618727.jpg

    edit the one with red covers the one that was in the truck
     
    Last edited: May 9, 2021
  4. Rusty Nail

    Rusty Nail Victim of Culture

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    Wow that's crazy lookin! Looks like the surface of the moon.

    If you "cant find one in your area" doesn't that pretty much make swapping guts worth it?
    I would think so if it were me ya but im no pro either.
    9 and a half or 10 is the diameter of the big gear?.. I think that's how you find out. ;)

    Stick a tape measure in it.
    :pedobear:



    :rolleyes:





    :waytogo: the differential.
     
  5. yepyep

    yepyep Junior Member

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    ya that makes sense ill measure the ring gear when i get a chance in a couple days and as far as being worth it i dont think i can hack changing the gears so itd be me dropping both rears off at the garage and potentially charging me more in labor then itd cost to buy a whole rear diff from the junkyard

    edit wait the ring gear serial numbers dont say the diameter?
     
  6. Blue Ox

    Blue Ox Turning Diesel Fuel Into Fun

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    They're 9.5".

    The 10.5" is the full floater.
     
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  7. Rusty Nail

    Rusty Nail Victim of Culture

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    Dude...
    Wtf?

    How is he gonna learn if you give him all the answers? Geez. That was gonna be fun...:( thanks a lot!
     
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  8. yepyep

    yepyep Junior Member

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    actually thanks i dont really wanna screw around i have enough stuff to do already
     
  9. Blue Ox

    Blue Ox Turning Diesel Fuel Into Fun

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    Sorry. It's early and my brain isn't awake yet.
     
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  10. bucket

    bucket Super Moderator Staff Member

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    If it ain't a show truck, honestly I'd just run the rusty axle with the right gear set in it already. Someone please correct me if I'm wrong, but I think the semi floater rear has 3/8" wall axle tubes like the full float rear. While it's really ugly pitting, it won't actually hurt anything.
     
  11. Curt

    Curt Supporting Member Supporting Member

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    Nope,the pitting will most likely not hurt anything (pitting).However,it looks like poo-poo.I say you need to dig in and swap internals.

    weekend warrior knocks gear swap outta the park...?you can do it.Everybody was a weekend warrior at some time.At least you have 100 videos on YouTube,and even if you didn’t use their product,Yukon Gear will give out some free tech tips.
     
  12. yepyep

    yepyep Junior Member

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    yeah it's not just the pitting either the brakes are completely shot even the dust Shields are rotted out I think you're right I'm going to have to swap the internals out the 373 is in just so much better shape I couldn't imagine putting money into the brakes on that Rusty junk axle
     
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  13. Rusty Nail

    Rusty Nail Victim of Culture

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    :headbang:

    :grd:
     
  14. Ricko1966

    Ricko1966 Full Access Member

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    Swapping gears is easier than swapping rearend. Just saying. Get over the fear it's really NBD you'll waste more time debating and thinking than just doing it.And for everyone trying to scare everyone else with if it's not within 1 100th of a nats ass perfect it'll burn up tomorrow and you'll never be able to have children. B. S. As long as everything is relatively close to right you won't have a problem.
     
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