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Vibration with NP208 & 4" Lift

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by GDBlazerFun, Jun 28, 2002.

  1. GDBlazerFun

    GDBlazerFun Registered Member

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    Vibration with NP208 & 4\" Lift

    Yes I'm a newbe...

    I'm currently looking at my options for lifting my 87 K-5 around 4". I heard nasty rumors about there being problems with driveline vibration. (Specifically caused by the slip-yolk from my NP208 transfer case and angles of the drive shaft.)

    Is just an urban legend or something I need to be concerned about? If it is true how do you beat it?

    Thanks for the help!

    /forums/images/icons/wink.gif
     
  2. Highlander

    Highlander 1/2 ton status

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    Re: Vibration with NP208 & 4\" Lift

    Yes you can get some bad vibs. But some people do and some don't, I've heard that some have dropped their tranfercase, This mite deppend on what lift you get as well, If you use blocks or go with new springs for the rear. I think most if not all blocks have a deg. made into them if you were to use rear springs you mite have to get shims to help with pinon angle. If that didn't work you could get a driveshaft with a CV joint at the slip yoke end. But like I said if you got a good kit you mostlikely will not have any prob. Have you thought about witch way you're going to go? And how much money are you going to spend? Also how much can you do you're self? It's not that hard to do. I hope this helps some what I know there are members that can go more in depth.

    Eric
     
  3. random

    random Registered Member

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    Re: Vibration with NP208 & 4\" Lift

    ive currently have a 4 inch skyjacker softride lift.no vibe probs ..do have rear shimmed and transfer lowered . good luck!! well worth it . ps im runnin 36s with 4 inch lift an cutout flares
     
  4. trailblazer87

    trailblazer87 1/2 ton status

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    Re: Vibration with NP208 & 4\" Lift

    I've got your trucks twin brother. I got a 4" suspension lift and had bad vibes at 50-60 mph and when I backed off the throttle. I have skyjacker 4" springs in the rear with 2" blocks, not sure if the springs sagged or the front springs lifted it more than the rear, the lift blocks were degreed (not sure how much, skyjacker made them) so they rotated the axle pinion side up,I had to lower the transfer case 1", and have had no problems since. The idea is to keep the u-joint angles the same. If it is really bad you can get a cv-axle, but they tend to be a little weaker. I recommend that you change to the larger 1-ton ujoints, and ditch the half ton gear on that driveline. Mine cost about $200 to convert, keep it in mind for the future. No matter what you do you will have increased wear on the u-joints, you will change them more often, just keep them well greased and they should last a good 6 months to a year, don't get the cheepies, try to find the oem spicer units, they tend to be better quality. Good Luck and Have Fun, hope this helps.
     
  5. fisher1648

    fisher1648 Registered Member

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    Re: Vibration with NP208 & 4\" Lift

    I've got an 87 with a 4" lift in the rear. I dropped the T-case 1" and had the rear driveshaft lengthened (cant remember the length but I can measure it). From what I understand, the long length of the output shaft of the 208 T-case is the reason for the vibe and when ya pull the yoke out (due to the lift) it vibrates. My set-up does not seem to vibrate.

    Hope this helps -
     
  6. GDBlazerFun

    GDBlazerFun Registered Member

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    Re: Vibration with NP208 & 4\" Lift

    Thanks Eric,

    I've decided that I'm going to do the ORD 4" Shackle flip in back! (Currently still trying to design front!)
    I'm trying to stay Cheap but do a good job... I'm a tinkerer and love wrenching on my rig! So I will most likely do all of the lifting myself with help of the Friends!

    I want to take my time and do it right... in stages so I don't over build (If that is possible!) and don't underbuild!

    Goal = Nice Rig, Good Condition, Streetable So I can drive too and from favorite wheelin spot! (And use as semi-daily driver!)


    Thanks
    Greg -
     
  7. scott87

    scott87 Registered Member

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    Re: Vibration with NP208 & 4\" Lift

    I did a 4" ORD shackle flip in the rear of my 87 recently. I did have some significant vibration, mostly due to the pinion angle after the flip. Lowering the t-case helps, but I ended up getting a CV shaft from Tom Woods Driveshafts. That really helped. But, the pinion angle needs to be just right for it to really work with the CV shaft. If not, then you will still get vibes, and you'll wonder why you just dropped all that money on a custom driveshaft. It seems that everyone's truck is a little different. You kind of need to do the lift and see what needs to be done afterwards. I do like the shackle flip, a bit of a pain to put in, but worth it overall. ORD is great and Stephen is very helpful. Good luck on the adventure!
     
  8. RLBstein

    RLBstein 1/2 ton status

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    Re: Vibration with NP208 & 4\" Lift

    And just to beat this into the ground. I have a Rough Country 4" lift on the front and ORD flip in the rear. The only thing I did to keep from having vibrations was lowering the crossmember the t/c sits on. The only thing I did was use the 1" shims that were already there. I just mounted them between the frame and the crossmember to lower it. I dont know if yours has those or not but its just another idea.
     

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