1. Registration trouble? Please use the "Contact Us" link at the bottom right corner of the page and your issue will be resolved.
    Dismiss Notice

Power Lock Parts Inter Change

Discussion in 'Early CJ5 and CJ6 Tech' started by Jeepsterjim, Jun 2, 2020.

  1. Jun 2, 2020
    Jeepsterjim

    Jeepsterjim Member

    Lincoln, CA
    Joined:
    Apr 25, 2019
    Messages:
    401
    The '71 d-44 flanged off set rear diff 30 spline has a power lock unit it that I was going to use BUT I came across a possible problem that hopefully someone can solve for me.

    The '71 diff has 3.73 gears----ring gear is stamped 41-11.
    So the Power lock is a series 3? since the diff has 3;73?
    if so, installing 5;38's won't work without useing a series 4 power lock?


    Have, a D-44 2 piece 19 spline axle diff with 5'38 and a power lock. 4 series???
    Is it possible to use the power lock from the 2 piece alxe, 19 spline and simply change out a few parts from the 3 series power lock?

    Would there be a clash with different bearings, ETC.

    what a mess!
     
  2. Jun 2, 2020
    Fireball

    Fireball Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Pullman, WA
    Joined:
    Feb 9, 2018
    Messages:
    5,622
  3. Jun 2, 2020
    oddfirejeeper

    oddfirejeeper Active Member

    Hamilton, MI
    Joined:
    May 5, 2004
    Messages:
    1,253
    if i remember correctly the bearings might be different between the 19 spline powr-lok and the 30 spline powr-lok. nickmil i think pointed that out to me when I was looking at putting 30 spline innards into a 19 spline case but i could be wrong
     
  4. Jun 2, 2020
    oddfirejeeper

    oddfirejeeper Active Member

    Hamilton, MI
    Joined:
    May 5, 2004
    Messages:
    1,253
    the case break is 3;92 and up for a series 4 in a 44
     
  5. Jun 2, 2020
    Jeepsterjim

    Jeepsterjim Member

    Lincoln, CA
    Joined:
    Apr 25, 2019
    Messages:
    401
    So, are you saying use the Power Lock 3 series and simply buy a thick 5.38 ring gear kit?
    I would not need to use a 4 series power lock?
    Interesting!
     
  6. Jun 2, 2020
    Ohiowrangler

    Ohiowrangler Member 2023 Sponsor 2022 Sponsor

    Newark, Ohio
    Joined:
    May 29, 2019
    Messages:
    270
    I'm running a 5.13 thick gear on a 3 series Detroit locker in the front 44, and a standard gear on a Detroit in the rear. Ron
     
    Fireball likes this.
  7. Jun 3, 2020
    Fireball

    Fireball Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Pullman, WA
    Joined:
    Feb 9, 2018
    Messages:
    5,622
    Yes, the lower numerical gears have a bigger pinion, so the ring mounting surface is further away. Higher numerical gears on a type 3 case leave a gap. Someone used to make spacers, but it sounds like they were no end of problems with bolts loosening. The thick gears are the way to go.
     
  8. Jun 3, 2020
    Jeepsterjim

    Jeepsterjim Member

    Lincoln, CA
    Joined:
    Apr 25, 2019
    Messages:
    401
    So I can use my existing Power Lock 3 series that now has 3.73 gears and simply install a thick 5.38 R&P set up and call it a day.
     
  9. Jun 3, 2020
    jeepdaddy2000

    jeepdaddy2000 Active Member

    Eagle Point oregon
    Joined:
    Jun 24, 2004
    Messages:
    1,132
    Might want to double check the side gear fitment as well. I seem to remember somewhere back in the cobwebs of my mind that the 19 spline side gears aren't interchangeable with the 30 spline ones inside the casing. Someone correct me if I am wrong.

    5.38's are super low. Are you sure your going to be happy with them?
     
  10. Jun 3, 2020
    oldtime

    oldtime oldtime

    St. Charles,...
    Joined:
    Aug 14, 2006
    Messages:
    3,466
    Internal parts for both series of D44 are fully interchangeable.
    All parts interchange excepting that 30 spline and 19 spline Powr Lok units require different sized journal bearings.
    That said know that there are two different versions of the 30 spline Powr Lok side gear cups.
    Early 30 spline units (early 1960’s) had two piece side gear cups while later on the decade DS went to one piece side gear cups. And yes these different side gear cups are interchangeable as a set.
    With standard open D44 differential cases one cannot swap side gears between the 19 and the 30 spline units.
    Got that ?
     
    Last edited: Jun 3, 2020
  11. Jun 3, 2020
    Jeepsterjim

    Jeepsterjim Member

    Lincoln, CA
    Joined:
    Apr 25, 2019
    Messages:
    401
    This rear diff and frt. diff with 5.38's is going into '47 2A with a F-134. Pretty much the gear ratio the 2A came with. I do have a O.D unit and plan on running 7:50 X 15 tires.
     
    Last edited: Jun 3, 2020
    Muzikp likes this.
  12. Jun 4, 2020
    jeepdaddy2000

    jeepdaddy2000 Active Member

    Eagle Point oregon
    Joined:
    Jun 24, 2004
    Messages:
    1,132
    This is probably what I was thinking of....
     
  13. Jun 4, 2020
    Keys5a

    Keys5a Sponsor

    Florida Keys
    Joined:
    Jan 23, 2014
    Messages:
    4,170
    7 or 8 years back, I used a "thick" gear on a 3 Series diff to get a lower gear. It worked, but barely! I ended up with no shims on one side, and a big stack on the opposite side of the case to get a good tooth contact. It worked out, but with no room to spare!
    Donny
     
  14. Jun 4, 2020
    Ohiowrangler

    Ohiowrangler Member 2023 Sponsor 2022 Sponsor

    Newark, Ohio
    Joined:
    May 29, 2019
    Messages:
    270
    What axle were you running?
     
  15. Jun 4, 2020
    Jeepsterjim

    Jeepsterjim Member

    Lincoln, CA
    Joined:
    Apr 25, 2019
    Messages:
    401
    diff is:
    1971 dana-44 off set 30 spline flanged diff that has 3.73 gears with a series 3 power lock.
    goal is to swap out gears to 5.38 and still have a power lock unit.
     
New Posts