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driveshaft lengthen???

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by bennevis, Sep 27, 2000.

  1. bennevis

    bennevis Registered Member

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    I have an add a-leaf with about 2" of lift and running 32's. I have to lengthen the rear drive shaft. Any suggestions on driveshaft replacement, what to do since it will be removed and what ujoints??? Any and all suggestions are welcome.
    Bennevis
     
  2. Blue85

    Blue85 Troll Premium Member

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    You have to lengthen the driveshaft? Most people with 4" lifts get along fine without ever lengthening the driveshafts. In fact, some run stock shafts with 6". With only add-a-leafs, you should be fine. At 2" of lift, you've increased the static length of the driveshafts by less than an inch. No point in trying to compensate for this unless there are some other factors that you didn't mention in your post.

    '85 JIMMY
    '90 paint/grill/trim 5"susp 33/12.5/16.5
    Fresh 350 B&M '87 TH700
     
  3. bennevis

    bennevis Registered Member

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    On the rear driveshaft where it goes into the transfercase, you can see about 2-3" of the shaft sticking out of the transfercase from where it used to be. Would this require it to be lengthened?
    Bennevis
    82' K5
     
  4. Rebel88

    Rebel88 1/2 ton status

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    I am running 6" lift and stock shafts. Granted they are a little off of what they used to be but if you need some info talk to Jesse aka Drivelineman. I am going to get him to build me shafts. He might have an easy remedy. It cant hurt to ask.

    Have you driven OVER a Ford lately?
     
  5. drivelineman

    drivelineman 1/2 ton status

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    let me know if you have any q's - be happy to help- thanks rebel88 - forwhlr@saber.net
     
  6. lowlevell

    lowlevell 1/2 ton status

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    Whoa hang on dude,I thought the same thing when i switched to a 14ff.Are you absolutely sure its sticking out that far?The drive shaft yoke will be worn (shiny),about 2" where it goes into the transfer.This is caused from regular driveing.Unless you have vibration or shaking i wouldnt worry about it


    One From None
     
  7. CK5

    CK5 In my underwear Administrator Premium Member GMOTM Winner Author

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    If you only have a 2" lift you should be fine, you could lower your t-case a bit to compensate, making the distance between the tcase and the pinion shorter, just move the spacers that are located above the frame to under the frame (tcase cross member).

    [​IMG]
    5,000 Pounds of American Rolling Steel
     
  8. Blue85

    Blue85 Troll Premium Member

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    The slip joint is like 5-6" long. When the truck is sitting still, you want to have at least a couple inches sticking out so that when your axle stuffs, the driveshaft won't collide with the rear of the T-case. With a shaft that is too long, you should add longer bumpstops. They will limit your articulation, but it is limited anyway by the slip joint. If you have too much slip joint sticking out, then you run the risk of the driveshaft falling out when the axle goes to full droop. This is a very bad situation because your truck is almost certainly moving and shaft will be flailing about until it hits a rock or stump or something. Many things can happen with a loose driveshaft front, almost none of which aren't awful. Also, you don't want to apply too much torque through a very short length of splines.

    At 6" of lift, it becomes something that you have to worry about, assuming that the rest of the drivetrain is stock. Lowering the T-case makes up a little difference. Swapping in a 14-bolt FF will also make up some difference.

    If you do need a longer shaft, you may be able to get one from a different vehicle, like a short-box pickup, that may be closer to the right length. Otherwise a drivetrain or machine shop can do it for you.

    '85 JIMMY
    '90 paint/grill/trim 5"susp 33/12.5/16.5
    Fresh 350 B&M '87 TH700
     
  9. bennevis

    bennevis Registered Member

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    Thanks for all the info.
    Bennevis
     

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