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  •  » Pinion Angle Sanity Check

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    12/26/2020 12:13 PM  #1

    zed
    Active Member

    Offline

    Registered: 2/23/2020
    Posts: 5

    Pinion Angle Sanity Check

    Looking for some help in verifying the numbers/angles I'm seeing for my driveline. Some background, 1968 Mustang Coupe with a 4R70W swap. I now have the transmission as high as it will go in the tunnel and I believe my angles were also changed by using the Eaton GT rear leaf springs along with lowering the front of the car.

    I finally found what appears to be the most accurate measurements by removing the driveshaft and putting the angle finder right on the trans output, and then putting a straight edge across the front of the yoke ears. (I've tried using the crank pulley and using u-joint caps, etc)

    Configuration:
    Trans Tailshaft pointing down
    Pinion physically pointing up (although angle is considered down towards the rear of the car)
    4 Degree shim installed 

    I struggled getting accurate measurements with my phone using the Tremec app. Even removing my case my phone has little nubs for buttons on each side. So I'm using a digital angle finder and this online calculator: https://spicerparts.com/calculators/driveline-operating-angle-calculator

    Transmission Angle: -3.33 degrees
    Driveshaft Angle: -2.58
    Pinion Angle: -2.54
    Operating Angle 1:  .75
    Operating Angle 2: .04
    Overall operating angle: .71

    My driveline vibration appears to be gone. I do worry that the 2nd operating angle is so small in regards to keeping load on the 3rd member u-joint bearings. My big debate is if I should go from a 4 degree shim on the 3rd member to a 3 degree. If I'm thinking this through correctly that would increase operating angle 2.  I realize I have more to learn here, so I appreciate any feedback and corrections. Thanks

     

    12/26/2020 12:37 PM  #2

    6sally6
    Hyper FYIFORD ADDICT

    Offline

    From: Surfside Beach,SC
    Registered: 4/02/2013
    Posts: 6,855

    Re: Pinion Angle Sanity Check

    Well zed............ (glad to have ya on the board!)
    I'm having a slight problem understanding your "issue".
    If the vibration ......"appears-to-be-gone"....let's get together and have a drink!!
    That's the answer to the whole vibration-of-my-driveline  problem many seem to have!!
    IT'S GONE  !!
    I would humbly suggest to take the old Mustang out  and  'wring-it-out' in every gear and if there is STILL no vibration start pondering the unanswerable (is that a word question of......if you having a cooling problem is it the radiator...the water pump...or the theromstat that's the fix!!!!
    Seriously....no vibe is a good thing, rejoice-in-it  and again welcome to the best board on the web!!!!!
    6sally6

    Get busy Liv'in or get busy Die'n....Host of the 2020 Bash at the Beach/The only Bash that got cancelled  )8
     

    12/26/2020 8:57 PM  #3

    Bentworker
    I FYI 24-7

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    Registered: 9/17/2017
    Posts: 472

    Re: Pinion Angle Sanity Check

    I’d say your good.

     

    12/27/2020 7:32 AM  #4

    TKOPerformance
    Hyper FYIFORD ADDICT

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    From: Newark, DE
    Registered: 12/15/2014
    Posts: 7,502

    Re: Pinion Angle Sanity Check

    If the vibration is gone I wouldn't spend time overthinking it.

     

    12/27/2020 12:08 PM  #5

    zed
    Active Member

    Offline

    Registered: 2/23/2020
    Posts: 5

    Re: Pinion Angle Sanity Check

    Thanks for the feedback guys. I was getting hung up on worrying about the angles. It has take a bit more work than I thought to work on the bugs.

    I played a lot with moving the angles around as I also believed the whining/noise in the rear end was due to the pinion angle. It's not as bad with the angle I'm at, but never went away completely. At this point I blame the new aftermarket gear set installed in the 3rd member. I had removed the rear for a re-inspection and everything looked good, so I'll have to decide what to do there at some point. (I'm going to live with it for now, holding out hope that it just needs more break-in, although that was a year ago)

       •Thread Starter
     

    12/27/2020 1:15 PM  #6

    Chaplin
    Senior 24-7 FYI Addict

    Offline

    Registered: 3/14/2015
    Posts: 1,027

    Re: Pinion Angle Sanity Check

    Maybe this will help. Although I think I agree with the others, if you have no vibrations, I think I'd leave well enough alone.

    https://www.diyford.com/ford-restomod-rear-suspension-guide/

     

    12/29/2020 4:53 PM  #7

    MS
    Forum Originator

    Offline

    From: Canyon Lake, Texas
    Registered: 1/24/2013
    Posts: 12,263

    Re: Pinion Angle Sanity Check

    ABDFI, a common MustangSteve acronym, surely applies here.

    Money you enjoy wasting is NOT wasted money... unless your wife finds out.
     

     

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