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No Vibe Driveline Secret Possibly Revealed.. Rene???

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by BorregoK5, Mar 1, 2002.

  1. BorregoK5

    BorregoK5 1/2 ton status

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    Theres been a lot of talk over non CV driveshafts having to have equal angle offsets at each end as opposed to CV shafts which have no angle at the rear end but rather the pinion is in line with the driveshaft in order to prevent vibes. BUT, a select few people on this board are running the non CV drivelines with the rear pinion in line with the shaft and have no vibrations. Well, I now have joined the ranks and think I know why, but first... for those of you , and I think Rene was one of them, that have the rear set up for CV but dont have a CV style driveline, and have no vibrations... the big question.

    Are you running a slip-yolk or a fixed yolk, and if its a fixed yolk, at which end of your driveline is the compression yolk on (the t-case side or the axle side)?

    Mine is a fixed yolk and with the compression yolk at the t-case it vibes, with it at the axle side, no vibe... hmmmm.

    I started with nothing and I still have most of that left! - <a target="_blank" href=http://community.webshots.com/user/borregok5> Pictures</a>
     
  2. wayne

    wayne 3/4 ton status

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    I have a slip yoke 241 with my stock shaft set up looking like it should be a CV shaft. The only vib. I have is when I let off the gas over 60 mph.

    See <a target="_blank" href=http://coloradok5.com/gallery/Waynes-Toy>Project Mighty Mouse</a> here.
    <font color=blue>Wayne<font color=blue>
    <font color=blue>Happy Trails<font color=blue>
     
  3. wayne

    wayne 3/4 ton status

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    BTW Rene's is like you said and that is where I got the idea to try it like that on mine.[​IMG]

    See <a target="_blank" href=http://coloradok5.com/gallery/Waynes-Toy>Project Mighty Mouse</a> here.
    <font color=blue>Wayne<font color=blue>
    <font color=blue>Happy Trails<font color=blue>
     
  4. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    I have a fixed yoke 205. The slip yoke part of the driveshaft is at the T-case end...more specifiaclly the driveshaft itself has the male end of the deal, and the T-case end of the shaft is the female end. I have no vibes at all and I regularly cruise at 75 to 80 mph on the freeway.

    My pinion is currently pointed about 1 degree low, just like an optimal CV shaft set-up. Every article I've read says that I should have a lot of vibes but I don't so i'm not changing it.[​IMG]

    I also think that the rear shaft length is a factor. I have the SM 465 so my rear shaft is the longest posssible in a K5 at roughly 47". My front shaft is only 27" though...

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
    <a target="_blank" href=http://coloradok5.com/gallery/project_T2> tRusty pics...</a>
     
  5. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Re: ramblings of a lunatic mind

    I have the shortest factory shaft with my 203. I set the pinion angle by rewelding the perch. The case is 5-6deg down from level. the pinion is 5 deg up from level. I also ran the truck full time for over 2 years with a 2.5 deg wedge in the front. NEVER a hint of drive line vide. Tire vibrate from busted belts, missing weights, bent rims...yeah plenty of that but the shifter for the 203 (bolts dirrectly to the case) is pretty smooth.
    I'm at a loss how having the pinon up for a CV on a non CV shaft can run smooth. Only thing I can come up with is the angle at the tranny is shallow enough that the vibration is minor to the point it not noticable. Everything I have read say's that if they are within 2-2.5 deg your usualy ok. I know I have seen them at over 4 and run seemingly smooth.
    I also think the driveshaft is factoring into this a lot. The guys running slip yoke seem to have a LOT more problems with vibe than the fixed yoke people. Almost everybody with a 208 has had to lower the case to cure vibration or go to a CV drive shaft. Those of use with fixed yoke 203's and 205's seem to have to do that much less. Usualy takes over 6 inches of lift for us to have a problem where the 208 trucks are having a problem at 4inches.
    A couple ideas as to why is since the slip shaft is inline with the shaft it's less prone to binding. A slip yoke it seems would get some upward push if the angles were severe.
    The slip yoke shaft is also lighter drive shaft. it's weight is on the ends mostly. The fixed yoke has conciderabley more weight mid shaft due to the slip shaft and splines. I bet that extra weight helps take some of the vibration out. The the slip yoke would have more of a tendancy to flail since the weight is located all at the ends. This is because when the one side was vibrating it would send the vibration to the oposite joint and would get transmited back since there is no counter vibration. Remember ALL drive shafst vibrate or better description is occilate. There is vibration there if there is any angle on the joint. The key is that the joints need to ocilate 180 deg out of phase of each other so the vibration is canceld out on the shaft and not transmitted to the rest of the drive line. Maybe that extra weight of the slip shaft is enough to dampen the vibration on the shaft.

    Women dig dents and flat paint!
    coloradok5.com/gallery/Grim
    75 Jimmy, Dollar
    Grim-Reaper
     
  6. Corey 78K5

    Corey 78K5 1 ton status

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    I got a flip with a 203 fixed end's on the shaft and the female end is on the t-case side. It's set up for a cv but I have zero vibe. Driven it on several trips and no problem at any speed 85 is probably as fast as I'v ever driven it though.


    Corey 78K5
    350CI, TH350, 203, Dana 44,12 Bolt, 4"lift, Shackel Flip, Sawsall and 35" BFG's
     
  7. 84_Chevy_K10

    84_Chevy_K10 Banned

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    All my friends trucks are like that too. My one friend in particular has a 12" Superlift in front with a homemade shackle flip out back (I think he has blocks too, but he might have different springs, I can't remember). His shaft is pointed straight at the pinion too, and no vibes for him.

    He has a longbed truck and a SM 465/NP205 too.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     

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