Differential swap

Discussion in 'Engine/Drivetrain' started by Perkolator, Feb 22, 2016.

  1. Perkolator

    Perkolator Veteran

    Joined:
    Mar 25, 2015
    Messages:
    368
    Likes Received:
    29
    Location:
    Citrus Heights, CA
    I'm kinda sure this will work but want to confirm before I open things up and drain my gear oil. I was cleaning up in my garage this weekend and saw my old 4.10 diff sitting there on a shelf. It's from my 93 4wd pickup. Hoping I can swap it in place of my 75 pickups 4.37 diff so I can drop my RPMs a little bit.

    I know the housing will physically bolt up, but was unsure of 2wd vs 4wd axles sliding into the differential carrier. I haven't looked up specs of axle spline counts etc yet, unfortunately everyone's lists start with the 79 pickups.

    So...Will it work?
     
  2. Perkolator

    Perkolator Veteran

    Joined:
    Mar 25, 2015
    Messages:
    368
    Likes Received:
    29
    Location:
    Citrus Heights, CA
    Ok even though all the Toyota info I've found regarding axle spline counts starts with the 79 and newer trucks, I'm fairly certain the older 8" diff is still going to be a 30-spline axle inside, so should be good to go on this swap :clapping:
     
  3. first80toyota

    first80toyota Addict

    Joined:
    Sep 8, 2012
    Messages:
    979
    Likes Received:
    14
    Location:
    Pacific Northwest
    Truck:
    '77 Hilux
    As far as I know it will work. If not atleast you already have it..

    Don't know if youre trying for MPG's or just a little lower rpms, but I have a 3.07 diff I have no use for.
     
  4. YOguyDA

    YOguyDA Addict

    Joined:
    Jun 20, 2009
    Messages:
    601
    Likes Received:
    26
    Location:
    Sacramento, CA
    Truck:
    1986 Regular Cab
    You have an 8" rear in your truck?
     
  5. Perkolator

    Perkolator Veteran

    Joined:
    Mar 25, 2015
    Messages:
    368
    Likes Received:
    29
    Location:
    Citrus Heights, CA
    Yes I believe so. Truck plate says W50 trans G105 differential which is 8" 4.37 gears if I read all the axle decode charts correctly. I know people swap diffs all the time but not much info I've found for older Hilux trucks. I just fingered through the Toyota FSM that I bought last week and even in there it doesn't say the axle spline count.
     
  6. YOguyDA

    YOguyDA Addict

    Joined:
    Jun 20, 2009
    Messages:
    601
    Likes Received:
    26
    Location:
    Sacramento, CA
    Truck:
    1986 Regular Cab
    Yeah, I can't confirm, but i doubt toyota would have changed the spline count...
     
  7. Bronchogg

    Bronchogg Member

    Joined:
    Feb 16, 2014
    Messages:
    34
    Likes Received:
    3
    Location:
    Salt Lake
    Truck:
    71 Hilux
    I know for a fact (I took it apart to mount an MKIII Supra LSD in it) that my 71 is a G-code and has 30 splines.
     
  8. Perkolator

    Perkolator Veteran

    Joined:
    Mar 25, 2015
    Messages:
    368
    Likes Received:
    29
    Location:
    Citrus Heights, CA
    Yeah, everything I see shows Toyota started out with a beefier setup then someone must have been like "hey, our product is doesn't break enough and we're spending extra $ in producing this truck, so lets tone things down a bit" hehe

    I still need to swap out my diff for a lower gear ratio, don't think I'll be using my 4.10 diff after taking the truck on the highway for the first time ever 2 weeks ago. She was definitely up there in the RPMs at cruising speed, sounded above 3500rpm to me, but still had plenty of get up and go from there. I will note my exhaust is stupid loud at an indicated 65-70mph cruising speed and definitely needs to be knocked down with something else. Need to take care of that and get a tach, add it to my ever growing list!
     
  9. Bronchogg

    Bronchogg Member

    Joined:
    Feb 16, 2014
    Messages:
    34
    Likes Received:
    3
    Location:
    Salt Lake
    Truck:
    71 Hilux
    I know I've read it somewhere but can't remember when Toyota decided to ditch the G-code (8") for the F-code (7.5"). I think it was late 70's. Seems a little strange considering they are so similar and even more strange that they went back to them in later years.

    The G-code is a beefy axle for sure - especially in the small and light 1st and 2nd gens.

    I need to swap my gears as well. The 4 speed tops out at about 50mph thanks to my smaller tires.
     
  10. Perkolator

    Perkolator Veteran

    Joined:
    Mar 25, 2015
    Messages:
    368
    Likes Received:
    29
    Location:
    Citrus Heights, CA
    Yeah, I'm planning to run smaller tires later too, hence the need for a gear swap. What are you going to use?
     
  11. Bronchogg

    Bronchogg Member

    Joined:
    Feb 16, 2014
    Messages:
    34
    Likes Received:
    3
    Location:
    Salt Lake
    Truck:
    71 Hilux
    I've got 4.10s now. If I end up doing a swap, I don't want to be geared too tall so probably. 3.90 or 3.73.
     

Share This Page