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rear axle breakdown

Discussion in 'GM Powertrain' started by 4by44ever, Nov 28, 2010.

  1. 4by44ever

    4by44ever New Member

    Hello,
    my rear diff housing broke, i think it's of driving bigger tires and heavy loads .
    That's why i would like to put in a stronger axle, looking around on the net makes me think of a dana-44 full floater with 3.73 ratio(so i can leave my frontside stock) i do hardly any off-roading with the gmc so a dana-60 looks a little overkill
    now i would like to know what donor car i need to look for to make the swap as easy as posible.(keeping shock location,brakes,tires,... in mind)
    for the moment im on a low budget so i need to be able to use stock brakes and wheel bold pattern.
    I also know i need another u-joint,but how do i know wich one and where to get it?

    here's some pic's it's a 4.8 L 1999 gmc sierra 1500 extended cab(with the 3 doors)
    i think it's a dana-35 with 3.73 gear ratio correct me if im wrong.

    keep on trucking :party:( untill your axle breaks):grrrrrr:


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  2. Crawdaddy

    Crawdaddy Moderator Staff Member Platinum Contributor 1000 Posts

    It appears you have the very typical GM 10-bolt axle. I'd say it's moderately unlikely that you have 3.73s in such a small truck. They're more likely 3.08s. Your only real upgrade would be to move up to a 14-bolt 1 ton axle. You can get them in 6 lug semi-floater variants that should match your front. They very typically have 3.73s or 4.10s in them.
  3. 2COR517

    2COR517 New Member 1000 Posts

    Your carrier is broken. The carrier is the weakest link, especially the G80. You might be able to just swap in a new Tru-Trac and be done with it. Much quicker, easier, and less money than swapping axles.

    If you are determined to swap axles, get a 6 lug 9.5" 14 bolt.
  4. 4by44ever

    4by44ever New Member

    thanks for the answers. i was also thinking of putting in a tru-trac but then i first have to make sure nothing else broke in the axle.
    about the ratio, i read somewhere that i had to count the teeth on the ring gear(it has 41) and devide it with the nr of teeth on the input pinion gear(11) or is this wrong?
    also on the ring gear there is a code :11-41 °073 1
    Will putting in a tru-trac make the assembly stronger?

    greetings and thanks for the input
  5. 2COR517

    2COR517 New Member 1000 Posts

    41/11 = 3.73 gears. Did chunks come out when you drained the lube? How about the magnet? Is it covered?

    If the ring & pinion gears have not been damaged by floating parts, you can definitely re-use them. Same for the bearings. But if you put in a Tru-Trac, you will have to replace the carrier bearings anyway. Pinion and wheel bearings are optional. If you don't touch the pinion, it's a real easy job to install the Tru-Trac.

    The Tru-Trac will definitely make the entire axle assembly "stronger" as it's the weakest link in the chain. Part of the reason it's stronger is because they use a different carrier bearing. GM shot themselves in the foot with the ten bolt. They went to larger diameter axle shafts - I don't know the year. Great idea to make them stronger. But rather than re-work the carrier to accept larger bearings, they just machined the carrier down to receive the shaft. As a result, they created a different weak spot. Couple this weak spot with the very UN-smooth operation of the G80, and you have failures. The Tru-Trac uses a "thinner" bearing. Larger ID, but the same OD to fit the housing.

    I would pull the axle shafts a bit, and remove the carrier to assess the extent of damage to the rest of the differential.
  6. silveradotrailblazer

    silveradotrailblazer New Member 1000 Posts

    I agree with 2COR517, if you don't have damaged ring&pinion just replace the carrier with the Tru-Trac, thats what I did in my Suburban after breaking my G80,twice.
  7. 4by44ever

    4by44ever New Member

    the decision has been made , since i don't do any hardcore trails with this one,but do need the extra traction sometimes, no open diff will do, and a full locker is not okay for hauling ,a TRUTRAC it is.
    I removed the shafts and carrier, everything else looks okay, there is some wear but no broken or chipped teeth on the gears so i should be okay doing it myself, i got the special tools from a friend .
    i hope to get the parts next week( i ordered with summit,there okay with international orders)

    thanks for the help
  8. 4by44ever

    4by44ever New Member

    Just an update and a WARNING
    After a few years i can say the tru-trac does the job well,only one warning:DO NOT re-use the old bolts that keep the diff to the ringgear,use THE NEW BOLTS that come with the tru-trac.
    I found it really hard to get the new bolts to the good torque so i used the old ones.The new ones kind of "bite"
    Now i now they have to.A few months ago there was a load bang and allot of grinding,when i went to look i noticed i suddenly had an extra checkhole in the diff-cover.
    So i limpt the car home(only 5 miles,luckely)
    I was thinking the whole thing broke down and was already cursing myself for not getting the 14-bolt.
    But hey,it was just one bolt that came out the ringgear,got stuck between the true-trac:great:(those things are STRONG )and cover and then went straigt true the cover,but all bolts where loose,changed them out for the new ones,checked it 2 months later and all is well.Good thing i did not get a heavy-duty diff-cover,i don't now what would have broken then.

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