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Another driveline question

Discussion in 'The Hokey Ass Message Board' started by oface, Jun 26, 2009.

  1. oface
    Joined: Aug 30, 2008
    Posts: 64

    oface
    Member

    I have a 58 Ford p/u short bed. Its a truck Ive been working on since the end of last year off and on. It has a 302/c-4 motor and tranny with the org. 9 in. rear end. Someone had lowered the truck before I bought it and didnt change the pinion angle. The pinion angle was at 10 degrees +, the tranny is 5 degrees -.I dont remember what the drive shaft was. The truck would shake all the time at highway speeds started wearing out the rear u-joint.I changed the pinion angle to 4 degrees +,the tranny is still at 5 degrees - and the driveshaft is at 3 degrees pointing down from the tranny. I also replaced the u-joint. When I accelerate to 60 it doesnt shake until I let off the gas. I checked the pinion for play and it seems nice and tight. The yoke going into the tranny has .011 play in it when you move it up and down. The output shaft moves up and down about an inch without the yoke on it,is this excessive play? Would this cause my vibration or are my drive shaft angles still off? Thanks for any help this has been driving me nuts,and yes I did use search it was very helpful.
     
  2. until you match up the pinion with the trans output shaft your gonna get vibration. take 5 degrees out of pinion angle and youll be fine
     
  3. oface
    Joined: Aug 30, 2008
    Posts: 64

    oface
    Member

    55 dude thanks for the reply. Right now the tranny is at 5 degrees neg. The pinion is at 4 degrees pos, so the pinion needs to be 1 degree neg? Thanks oface.
     
  4. oface
    Joined: Aug 30, 2008
    Posts: 64

    oface
    Member

    Sorry guys misunderstanding I have changed the pinion angle. Its been changed to 4 degrees pos. Now it only shakes when I let off. I tried to set at 5 degrees but when the springs settled it ended up being 4+. Let me go back and read my post maybe I wrote something down wrong thanks,oface.
     
    Last edited: Jun 26, 2009

  5. oface
    Joined: Aug 30, 2008
    Posts: 64

    oface
    Member

    Come on you guys help me out here.
     
  6. roundvalley
    Joined: Apr 10, 2005
    Posts: 1,776

    roundvalley
    Member

    I don' think a difference of 1* is causing your problem. What is the 1" travel on the output shaft all about?
     
  7. oface
    Joined: Aug 30, 2008
    Posts: 64

    oface
    Member

    when I pull the drive shaft out you can move the output shaft 1 in up and down,with the driveshaft installed you can move it .011.
     
  8. Ok since you are having a problem understanding what everyone is saying. your pinion angle should match the angle of the tranny output shaft or the angle of the crank shaft which will be the same as the tranny output shaft. You can be a little off without suffering severe problems.

    The wobble of the output shaft/tailshaft on your tranny seems a little excessive to me. So that is something you might look into. But you could have all kinds of other problems like the rear being a little loose ot the driveshaft being out of balance or bent or???

    Start with the easy stuff first. Looks like you have done that by adjusting ot trying to adjuist your pinion angle.

    Jack your truck up now turn the rear wheel back an forth. How far does it turn before it takes up the slop in the gears? While you got it up grab onto a wheel and wiggle it around. is there slop in the axle bearing? Remind yourself that you are dealing with a 50 year old rearend. They usually don't get freshened unless they blow or they belong to a racer. so your rear may need to be freshened up.

    While you got it up there take a coat hanger and attach it to something solid and reach and and touch the drive shaft with it. This is a poor man's dial indicator. Turn the wheel around several times does your drive shaft stop touching the coat hanger at any point or does it try and push the coat hanger out of the way. Then you may have a run out problem, IE the drive shaft isn't straight. If this is the case drop drive shaft and fly to the nearest machine/drive shaft shop and see if it can be rectified.

    I could go on for hours but I have a Willys to attend to. Good luck.

    Benno
     
  9. oface
    Joined: Aug 30, 2008
    Posts: 64

    oface
    Member

    Thank you Benno for the reply Ill check the driveshaft and axle bearings this afternoon.
     

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