Differential Advice

Discussion in 'Differential & Driveline' started by vicnation, Nov 12, 2017.

  1. vicnation

    vicnation Member

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    First Name:
    Tristan
    Truck Year:
    1976
    Truck Model:
    k10
    Engine Size:
    350
    In my 1976 K10 which is used only on the street and sometimes for pulling a boat, I have the D44 and a 12 bolt rear. I plan to change the gear ratios to 4.10 and install a 4sp automatic for highway use. Would it be worth it to change the rear to a 14 bolt SF that already has a 4.10 ratio? There is one in my area from an 82 suburban 2wd for $300 but I don't know if there would be fitment issues. Also, can I get 6 lug axles for a 14 bolt SF or would it be more economical to do the front conversion to 8-lug?
     
  2. HotRodPC

    HotRodPC Administrator Staff Member

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    6.2 to Gas???
    The 14B Semi Float will bolt right in. Not sure on the driveshaft length but it's gotta be real close. I hear 6 bolt axles are available but it's later model trucks and must be from a 4x4, not a 2x4 since the 4x4 axles are a bit longer. $300 seems steep though for a 14b Semi Float. I see them around here for $150 to $200 frequently in good working order.
     
  3. Craig 85

    Craig 85 Full Access Member

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    Truck Year:
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    Truck Model:
    K30 SRW
    Engine Size:
    454/TH-400/NP205
    I did the swap in my last truck, a '79 K15. I picked up front and rear axles from an '82 3/4 ton for $400 (4.10's and a limited slip rear end). I listed some of the parts below. I had to have my rear driveline shortened. You can use the master cylinder for a '76 3/4 ton. You just need to swap the brake lines at the master cylinder as the reservoirs are reversed. You will also need axle plates for a 3/4 ton axle as the axle diameter is bigger in the rear. I had a 10 bolt in front, so for me is was easier to just swap the whole front axle. Due to changing to the larger rear brakes, it locked up easily. I was going to put in and adjustable proportioning valve to fix this, but sold the truck.

    Rear U-joint Spicer 1310-1350 Part# 5-460X or O’Reilly’s – Precision U-joint Part# 348
    (3.219 / 1.062 to 3.625 / 1.188)

    Master cylinder Napa NMC M2085 - 1979 GMC K20 w/“JB7” 13” rear brakes
    Front brake caliper Napa CAL SE4674 (LF)
    Front brake caliper Napa CAL SE4673 (RT)
    Front brake pads Napa UP UP7084AM
    Rear brake shoes Napa UP UP451R
    Rear brake drum Napa ND 4401348
    Rear brake cylinders UP37290
    Parking brake cable Napa UP93228 (LF)
    Parking brake cable Napa UP93228 (RT)

    IMG_1098.JPG
     
  4. vicnation

    vicnation Member

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    Thank you for the information. I appreciate it. I'll do some more digging for a better deal.
     
  5. HotRodPC

    HotRodPC Administrator Staff Member

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    That's the best bet right there. Find you set of axles for $300-$400. Then you can also sell your half ton axles for $200-$250.
     
  6. HotRodPC

    HotRodPC Administrator Staff Member

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    I'll add, or just sell your rear axle for $100-$150 whatever you can get out of it, and save your front axle for spare parts. They're worth holding onto. Not all of us have $1000 to buy a Dana 60 front, and then another $800-$1000 to go through it with new bearings, kingpins and cost of the conversion. Sooo, I keep my old front 10 bolt. If I break an axle, stub shaft or carrier, because if you wheel 10 bolts hard it's eventually going to happen, just a matter of when, then I don't have to go shopping for the parts and shell out the cash. I've already got it and for what I'll get out of that front axle, it'll cost me to buy just 1 axle or 1 carrier.
     
  7. Honky Kong jr

    Honky Kong jr Super Sarcastic Man

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    Ahhh 10 bolts are crap I will come haul them away and won’t charge you....:D
     
  8. HotRodPC

    HotRodPC Administrator Staff Member

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    That's what I'm saying. I got one of mine for FREE just for hauling it off and getting it outta his way. If and when the time comes I break my front axle, anything with exception of the ring and pinion, I've got spare parts. Axles, Stubshafts, knuckles, carrier, hosuing, etc. And when the time comes, whoever wants these 6 lug hubs and rotors, I won't need them but it's not a bad idea to have a set of spare hubs and spindles around either.
     
  9. Big Beast

    Big Beast Supporting Member Supporting Member

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    First Name:
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    Truck Year:
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    Truck Model:
    K5 Full Size Blazer
    Engine Size:
    5.7 L TBI
    Getting Ready to put 14 's under my blazer. The rear end is a 410 gear ratio but its missing the diff lock does anyone Have one they want to sell or can give me advice where to get one ?
     
  10. shiftpro

    shiftpro Full Access Member

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    Many of the older D44s had a flat spot on top of the passenger knuckle which is a place to install a steering arm for.........
    the best steering/handling mod ever.....cross over steering!
     

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