1991 F-Superduty Rear differential

Discussion in '6.9L IH & 7.3L IDI Diesels' started by 65sixbanger, Aug 21, 2018.

  1. 65sixbanger

    65sixbanger Full Access Member

    Posts:
    1,288
    Likes Received:
    1
    Joined:
    Mar 4, 2009
    Location:
    New Braunfels, Texas
    My soon to be service truck has a 5.13 gear set in the rear differential. I would like to swap this set out for a taller set because max speed is about 50-55 right now.

    I have seen several posts and threads about nobody making parts for these early dana 80's, but I have found Yukon gear sets readily available and decently priced all over. Has anyone swapped gears in one of these trucks with this axle? Its a early Dana 80 that has disc brakes.

    https://www.randysworldwide.com/product/yg-d80-430/

    The url is kind of what I am looking for

    -Lance
     
    centennial60 likes this.
  2. towcat

    towcat Administrator Staff Member

    Posts:
    18,103
    Likes Received:
    1,299
    Joined:
    Jun 24, 2004
    Location:
    SantaClara,Ca/Hamilton,TX
    Dana 80's were morphed into many sub-variants. I've tried putting in the the dodge gears into a 88-98 D80 with no sucess. biggest issue is the housing. it is cast for the 5.13 center and 4.63 is the best you can do. check your governor and throttle cable, I can top out at 75 mph with the throttle matted loaded or unloaded.

    P1040574.JPG
     
    210Tumbleweed likes this.
  3. 210Tumbleweed

    210Tumbleweed Registered User

    Posts:
    45
    Likes Received:
    19
    Joined:
    May 7, 2018
    Location:
    Texas
    Ditto that Mr.Towcat...75 with the Zf-5 (er...unloaded). But loaded mine screams at an even 68...my 5th is a tad on the pudgy side.

    And for the OP...Yeppers I've got the 5.13 blues too, can't seem to find much. Somebody had suggested looking into 2006 and up "short busses" of the Ford variety, for a straight swap in unit? I haven't done the research yet...I'm hoping for 4.11 or 3.73's (should alleviate my FUEL bill issues....er....somewhat).

    Please keep on posting whatever info you come up with...

    P.$. I spoke with a guy at Randy's a few months back...and he had to call me back, but after my specifically asking for pricing on Dana/Spicer (Eaton really) and Timken bearings, he came back with a quote that wasn't much different than the Yuckon's....
     
  4. 65sixbanger

    65sixbanger Full Access Member

    Posts:
    1,288
    Likes Received:
    1
    Joined:
    Mar 4, 2009
    Location:
    New Braunfels, Texas
    Towcat... when you mean its cast for the 5.13 how does that affect the fitment of any other size? Wouldn't the overall ring diameter be the same?

    Also, on the randys site they show different gears for a bigger or smaller carrier. Was this an option when you tried to fit the dodge gears? They sure show a lot of correct fitments for these older F450's. Seems like they would've taken note if there were complaints of them not fitting. Idk just a thought.


    Thanks
    -Lance
     
  5. Macrobb

    Macrobb Full Access Member

    Posts:
    1,718
    Likes Received:
    693
    Joined:
    Jun 12, 2016
    Location:
    North Idaho
    Depending on the tire size, have you thought about just finding a complete 10.25 dually axle to swap in? Might be easier/cheaper.
    And, of course, parts are easy to come by, being pretty standard.
     
  6. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

    Posts:
    4,497
    Likes Received:
    2,424
    Joined:
    Jul 27, 2015
    Location:
    Bulverde, Texas
    f-superdutys use a narrowed rear frame, so a normal 10.25 wont work unless its from a c&c truck, which are pretty rare. You will also be going from four wheel discs to rear drums, so the valving will need to be changed at the master cylinder. I believe the u joint series is different as well.
     
  7. austin92

    austin92 Full Access Member

    Posts:
    562
    Likes Received:
    67
    Joined:
    Jul 20, 2016
    Location:
    Brazil. IN
    I looked around a little and the only carrier split I could find was 3.73/4.10. There was an arb air locker that stated 4.56 up. With that said, I don’t understand why you couldn’t put 4.10s on your existing carrier. Couldn’t see this being a casting issue like the dana 61


    Sent from my iPhone using Tapatalk
     
  8. 210Tumbleweed

    210Tumbleweed Registered User

    Posts:
    45
    Likes Received:
    19
    Joined:
    May 7, 2018
    Location:
    Texas
    I could be misinformed (not like it's the first...er...second) but the dude I spoke with at Randy's said the difference between carriers determines which gear-set one needs, same ratio different part numbers (most importantly different DIMENSIONS).
    And I didn't understand myself at first...

    ERGO: if you look on RWW website there's two listings for Dana 80/4.10, one has a "T" at the end o' said part number and one doesn't.

    Axle Stamped/Tag Numbers are key to getting the right stuff...the first time.
     
  9. mackinaw80

    mackinaw80 Registered User

    Posts:
    6
    Likes Received:
    2
    Joined:
    Feb 17, 2017
    Location:
    Illinois
    I have a '92 F Superduty that had 5.13's. It was out of fluid when I got it, I missed it and the ring/pinion was toast. I googled the crap out of it and found the carrier break is at 4.10. I put 4.11 (they have a set right above the break) with no modifications. Speedo reads off the carrier, so it does not affect the speedo. Torque on the pinion nut it pretty high and you will need a big torque wrench to pull it. I have no complaints. My IDI at 13,500lbs will roll 80mph. First gear is actually useful now.
     
  10. chillman88

    chillman88 Supporting Member Supporting Member

    Posts:
    1,500
    Likes Received:
    749
    Joined:
    Feb 22, 2017
    Location:
    Central NY
    My limited undersanding is the "T" means it's a "thick" gearset.

    The carrier break allows for the ring gear to be closer to or farther from the pinion gear so there's still enough "meat" there when using the... Numerically higher? gearset. I can't remember which direction it goes. I think numerically higher gears would need the larger pinion gear but I don't know for sure. The "thick" gearset would be used to "bypass" the carrier break and use the "wrong" carrier with those gears.

    Again I'm not sure which direction it goes but that's my understanding. I hope that at least makes a little sense for ya.
     
  11. mackinaw80

    mackinaw80 Registered User

    Posts:
    6
    Likes Received:
    2
    Joined:
    Feb 17, 2017
    Location:
    Illinois
    Higher gear ratios (5.13:1) have a smaller pinion. 5.13 pinion rotations vs 3.73 pinion rotations per 1 carrier rotation. Higher gear sets need more rotations, per carrier rotations, hence smaller

    As the ratio goes down (3.00:1), the pinion gets larger and the ring great moves to the left (away from the pinion location, when viewed from the cover).

    The 4.10 above carrier is closer to the pinion nominally. So you can only go down to the number right above the break, without changing the carrier. The larger pinion makes the ring gear too thin.

    The 4.09 and below carrier is further away from the pinion. This is where the thick gear set comes in. You can take a 3.00 geared vehicle up to a 5.13 (and higher to a point) if a thick set is available. Reality, you could put a spacer behind the ring gear a non thick gear set and achieve the same goal of a "thick" gear set. If you put a std and thick set side by side, the only difference is how much material is under the teeth, on the threaded side.
     
    chillman88 likes this.
  12. 210Tumbleweed

    210Tumbleweed Registered User

    Posts:
    45
    Likes Received:
    19
    Joined:
    May 7, 2018
    Location:
    Texas
    EUREKA!!! AH....huh???
    So...okay....I'll say it first. Sometimes I'm a...uh...little slow. But that's primarily due to the 5.13's, I've been blessed with...I wanna go faster, I really do. :bail

    (Seriously not intending to hijack this thread...my apologies to the OP.)
    SO...IS THERE A WAY TO GET THERE~> Keep the Dana 80 with 4.11-3.73 gearset; FROM HERE~> aforementioned D80 with 5.13's... and truly know at least the right parts are ordered?
    Or should one just....ppfffwshtttt (sound effects...'0,o`) pull a big ol' pair o' dice out and...uh...trust that the parts person on the other end of the phone, actually knows what they're doing?

    To "T"; or not to "T"? For me...I think that might be the question??
     
  13. chillman88

    chillman88 Supporting Member Supporting Member

    Posts:
    1,500
    Likes Received:
    749
    Joined:
    Feb 22, 2017
    Location:
    Central NY
    That would depend entirely on the return policy and your willingness to do the same job twice. If they'll take them back I'd order the thick ones and give it a shot. If they won't take them back.... I wouldn't bother.

    You'll be able to tell if they'll work by the time you check the gear pattern.
     
    210Tumbleweed likes this.
  14. mackinaw80

    mackinaw80 Registered User

    Posts:
    6
    Likes Received:
    2
    Joined:
    Feb 17, 2017
    Location:
    Illinois
    If you have 5.13 gears, the lowest you can go is 4.11, without doing a carrier swap. I have done this, personally, in my drive way. You can believe me more than the parts guy.

    The same applies going the other way. From the lowest supplied gear to the break point (4.10:1), it's simple. The "Thick" gear sets jumps the carrier break point and avoids the carrier swap.
     
  15. mackinaw80

    mackinaw80 Registered User

    Posts:
    6
    Likes Received:
    2
    Joined:
    Feb 17, 2017
    Location:
    Illinois
    So it appears you can get a "Thin" 3.73 gear set to take you under the carrier break.

    https://www.drivetrainshop.com/Dana_80_s/92.htm

    My reading, years ago, led me to believe that Ford and Dodge/GM used different D80's. I don't know the specifics of that.
     

Share This Page