Rear diff??? And gears

Discussion in 'F/I Mods & Tuning' started by shane881510, Jun 15, 2018.

  1. shane881510

    shane881510 Member

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    what diffs can we use to put in 4.10 gears and such. Need to start getting this t56 swap ready. Got eyes on a trans. What year models will work in our housings.
     
  2. Nashman

    Nashman Active Member

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    4x4v has the same diff should be easy to find one after market
     
  3. shane881510

    shane881510 Member

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    Thanks, just need to find a new diff that will hold the bigger 4.10 gears.
     
  4. Nashman

    Nashman Active Member

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    most cases you can just notch the opening so the ring gear can slip on past but best to find out the depth with a tape
     
  5. AZ Sun Lover

    AZ Sun Lover Member

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    Taco's 2005 plus have the carrier you're looking for but the X & 4 banger manuals.
    You have to buy another carrier because the OE gear in an X is 3.09 or 3.13 (don't quote these numbers) and 5 lug 4 cyl manuals have 3.31. Then the carrier changes when you get to a carrier for / with 3.58 and up!
    I went from the stock tires 26.8" with 3.31 gears, to 30" with 3.73. This made a night and day difference!
    That's going from approx 3.3 gear to a 3.7 gear and your going from a 3.1 to a 4.1 gear. That's a Lot! God the T56 trans must have some tall gears‼️
    If you buy a complete carrier (edit sorry 3rd member) from a 4 cyl 4x4 with a manual transmission it will have 4.10 gears. Also 1st gen. Tundra's have 3.90 gears. All Pre-runners, 4x4, 6 lug Tacoma's have 3.73 gears. Manual or automatics.

    Good luck,

    Oh, if you do the swap please let me know because I'm interested in a OE 6 spd. trans. :)
     
    #5 AZ Sun Lover, Jul 18, 2018
    Last edited: Jul 19, 2018
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  6. x-runner kid

    x-runner kid Active Member

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    So a stock X 3rd member will not fit a 3.73 gear even with a different differential? Or when you say carrier are you referring to the diff itself?
     
  7. AZ Sun Lover

    AZ Sun Lover Member

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    The carrier is the part that holds the ring & pinion gears just like a Ford.
    The 3rd member is the carrier, ring gear and pinion gear, plus mis parts.
    If you want 3.58, 3.73, 3.90 4.10 or a lower gear you should just buy a complete 3rd member and new gasket. The Toyota gasket needs to be soaked in water to be installed. Just drain the fluid, pinch & removed the brake lines, losen the parking brake cables, remove the 4 nuts on the back side of the drum brakes and slide out the axles about 3" with drums attached. Now removed the nuts that hold the 3rd / carrier clean off any old gasket, install new gasket soaked in water. Re-install in reverse, bleed brakes, fill with lube, test drive, enjoy the new performance!
    The 3rd. member in the X is worthless! It took me 6 mos to get a $100 for my 3.31 with less than 4700 miles.
    Installing the 3rd member / carrier is a piece of cake installing gears is a job for a pro! They are very precise and take special knowledge to setup. If done incorrectly you're asking for trouble! Not bad to do if you have someone who's has the knowledge and a few specialty tools.

    Good luck!
     
    #7 AZ Sun Lover, Jul 19, 2018
    Last edited: Jul 19, 2018
  8. x-runner kid

    x-runner kid Active Member

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    Well the carrier only holds the pinion gear and the differential. The ring gear is attached to the differential itself which is mounted on both sides. I don’t see why the ring gear wouldn’t fit since they are both 8” ring gears and both have the same amount of gear notches on them. The pinion on the factory 3.15 rear has 13 teeth and the 3.73 has 11. I guess if you tried to take the 3.73 gears out of a trd they wouldn’t fit in the stock carrier but if you bought the correct gear set it should fit the 3rd member just fine.
     
  9. AZ Sun Lover

    AZ Sun Lover Member

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    The machining where the pinion sets is different.
    If you think you can make it work go for it! Sorry to say you been warned.
    How do I know this? I also changed the gears in my Tacoma twice!
    So been there done that!
     
  10. x-runner kid

    x-runner kid Active Member

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    Damn well I guess I’ll find out cause I’m about to drop parts off at my diff builders shop. How is it that urd sells a diff with 4.10’s ? Or is it that they sell it as a whole 3rd member? I believe you don’t get me wrong you have done it I have not. So if my diff builder can’t make it work what carrier would I need? My plan is if it doesn’t work I’ll go to the junkyard and get a different 3rd member.
     
  11. AZ Sun Lover

    AZ Sun Lover Member

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    So you're dropping off the 3rd member from your X and or another X and 4.10 Ring & Pinion to be charged?
    Ok, Good luck and let us know how it works out. I'm guessing your gear guy is familiar with Toyota 8.4 diffs? You can call URD and ask them too.
    Oh, "junk yards" get good $$$ for 3rd members!
    By time I purchased another 3rd then purchased gears to be installed it was cheaper to buy a new one from Toyota. I paid just under 1k for a new 3rd out the door. And aftermarket gears are 4.11.

    AZ
     
    #11 AZ Sun Lover, Jul 19, 2018
    Last edited: Jul 19, 2018
  12. x-runner kid

    x-runner kid Active Member

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    I let my diff guy know what you said he doesn’t think it will an issue. He has done a lot of Toyota diffs and is very familiar with the 8.4. All the parts are brand new Yukon gear parts. 3.73 ring and pinion gears. Tru-trac diff.
     
  13. AZ Sun Lover

    AZ Sun Lover Member

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    What gear is in the diff now?
     
  14. x-runner kid

    x-runner kid Active Member

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    The stock 3.15 gear.
     
  15. AZ Sun Lover

    AZ Sun Lover Member

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    Ok, willing to make a friendly little wager that the 4.10 / 4.11 gears don't fit into that carrier / 3rd member!
    Say $20,000.00? But I'm willing to take $20 from you! Sorry bro but been there done that! I also had to learn the $$$ way!
    You will need a carrier / 3rd member that has 3.58 or lower. i.e. 3.73, 3.90, 4.10......
    If you're are wanting a 3.73 gear you be way better off looking through TW classifieds. I have seen them listed for $400 or less with a lot of miles. Then all you will need is a bearing kit, crust washer and mis shims for a rebuild. You don't know if the previous owner got water in the diff and didn't service it. It's cheap insurance to go through before install.
    Hey I'm truly sorry but like I said been there done that‼️
     
    x-runner kid likes this.
  16. x-runner kid

    x-runner kid Active Member

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    No wager lol. I’m hoping my diff guy can get the new 3.73 gears to fit. If not I already have another plan of attack. I already have everything I need to rebuild the diff. Bearings seal and I don’t need crush washers because my diff guy is doing a crush washer elimination so it will be more reliable and easier to service if need be in the future. If he can’t get it to work I’ll just get a 3rd member and gut it and put all my new parts in it. If he gets it to work I’ll let you guys know and let you know how he did it too.
     
  17. x-runner kid

    x-runner kid Active Member

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    So just like you said I needed a different carrier. Too bad I didn’t know that before I already had all my parts but it’s ok I found a carrier for pretty cheap that will work so I’m happy. Will have the 3.73 gears and the tru-trac and basically everything in the rear brand new.
     
  18. AZ Sun Lover

    AZ Sun Lover Member

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    Truly Sorry‼️
    I was the same! I couldn't understand why or how it could be different but they are!
    My I ask why such a drop in gears?
    I have a gutless 2.7 and up sized the tire by 2.2" (fill in the wheel wells)
    Plus I can't go any more than 1.5" of drop in the front and keep alignment in specs. I have a small stagger on rubber & wheels. I'm not installing the DJM LCA's they look scary‼️ I wouldn't mind trying the UCA's but can't get any feedback on if they would help my issue.

    Back on topic,
    AZ
     
  19. imom

    imom Member

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    I went from stock 3.31 to 3.73 gears via using the V6 3rd member. Just be prepare for the MPG drop. From 3.15, I would go 3.58...but just my 2 cents. If I had to do it again, I probably do 3.58 3rd member swap from 4 cyl auto for my 5 lug. 3rd member swap is easier and guarantee swap vs the gear swap.
     
  20. x-runner kid

    x-runner kid Active Member

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    Well finally got everything back together yesterday. I am running a slightly larger than stock rear tire and the 3.73 is the perfect gearing for me. I do a lot of autoX and drag stuff. Mileage doesn’t matter either since my truck is just a weekend toy. Going to a 3.73 isn’t much of a difference when you think that the prerunners and offroads run a 3.73. When my diff broke the side gear it was time to upgrade figured screw it might as well go full on race truck lol.
     

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