Register now to get rid of these ads!

Ford nine inch

Discussion in 'The Hokey Ass Message Board' started by bogart62, Mar 19, 2012.

  1. bogart62
    Joined: Dec 20, 2006
    Posts: 180

    bogart62
    Member

    Shaking out all the little things on my "55 GMC. One thing is that it feels real rough when making turns. I have a Ford Nine inch posi for the rear end. Had someone look at the truck while I made turns in my driveway and you can hear the roughness (lack of a better word) in the turns coming from the rear end. I will check gear fluid level etc. Any ideas?
     
  2. 64gal
    Joined: Jan 18, 2007
    Posts: 145

    64gal
    Member

    I believe a Ford tractionlok needs a friction modifier(oil additive) in the oil . If the oil is old, change it, if its fresh, try adding the additive(parts store or ford). Goodluck.
     
  3. bogart62
    Joined: Dec 20, 2006
    Posts: 180

    bogart62
    Member

    Thanks. It's a fresh set up. New ring and pinion with the orig. posi unit. I had it all put together and had a guy install it. No smarts needed to fill it with gear oil. He could have left out the additive. No drain plug on the rear, so I may have to suck out some gear oil to make room for the additive. Thanks for the reply. Stay tuned...............
     
  4. 6deuce32yblock
    Joined: Oct 26, 2007
    Posts: 134

    6deuce32yblock
    Member

    definitely needs the additive.add it and i think you will see and feel the difference:)
     
    Register now to get rid of these ads!

  5. bogart62
    Joined: Dec 20, 2006
    Posts: 180

    bogart62
    Member

    Thanks. Guess I am not the only one up early. Appreciate the input..

    Kent
     
  6. 40fordtudor
    Joined: Jan 3, 2010
    Posts: 2,503

    40fordtudor
    Member

    Beat me to it---
     
  7. There is a break-in proceedure for new gears. You might want to be sure that is done correctly also. Something like drive a few miles and check for overheating. Do this three times. Then a 200-250 miles trip and change the oil.
     
  8. Imperial Kustom
    Joined: Dec 20, 2007
    Posts: 269

    Imperial Kustom
    Member

    As said before, definitely sounds like it needs a friction modifier (additive). ALL clutch style limited slips use a friction modifier. Don't worry about removing any oil from the rear, the additive comes in a little 3.8oz bottle. Just squeeze it in there. Definitely use the Ford Racing kind. Trust me here, I've built thousands of diffs and the Ford stuff just seems to work best.

    Oh yeah, do yourself a favor and don't run synthetic oil either if you drive the car a lot. Just good ol' fashioned EP 80-90. In my experience, synthetics break down to far and cause premature wear and destruction in diffs.
     
  9. bogart62
    Joined: Dec 20, 2006
    Posts: 180

    bogart62
    Member

    Thanks guys. Will do additive tonight and will advise of the results.



    Kent
     
  10. Reminds me of a similar problem I had with a 65 El Camino 327, 300 HP, 4 Speed years ago. Kept replacing clutch discs and pressure plates cause It wouldn't come of the line without chattering. A friend of my Dads who was an auto mechanic had me drive it in a circle in a parking lot. You could feel the rear end waddle. Added GM friction modifier and all was well. Expensive lesson.
     
  11. bogart62
    Joined: Dec 20, 2006
    Posts: 180

    bogart62
    Member

    Update. Put in the friction additive and about 12oz. of 80-90 gear oil. ( a little low) Did circles in a parking lot going left then right. Seems to be loosening up. I'm thinking this is not an instant fix maybe have to get a few miles on it? Thanks.

    Kent
     
  12. bogart62
    Joined: Dec 20, 2006
    Posts: 180

    bogart62
    Member

    Ford 9" posi is defintely loosening up. I like it. Real different from the Tru-trac posi in my '37. don't even know it's there till it bites. However, in my '55 GMC the original type posi really goes with that truck. A little rough, you know it's there kinda thing. Thanks for all the input. Friction modifier is killer stuff.

    Kent
     

    Attached Files:

    • 035.JPG
      035.JPG
      File size:
      121.5 KB
      Views:
      41
  13. fab32
    Joined: May 14, 2002
    Posts: 13,987

    fab32
    Member Emeritus

    Put in the friction modifiers and your just defeating the positraction effect. The clutches grab each other (friction) and cause the axles to turn the same. With the modifers the clutches slip defeating the action created by the posi unit. Won't affect a new unit very much but a worn unit will almost useless if the clutches are allowed to slip.

    Frank
     
  14. newrider3
    Joined: Aug 19, 2010
    Posts: 62

    newrider3
    Member


    Ford specs call for the additive for all factory type limited slip rears.
     

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2020 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.